We will pretend for a moment that the stock market is actually tied to the real value of companies these days... Which is becoming a more and more dubious thing to believe, but let's pretend...
Others have given a better synopsis of the oddities going on in the oil market than I can, but I'll give a bit more information on the markets.
I think what's confusing you Mike, is that a lot of analysts tie the economy really closely to the stock market, which is not really true. It doesn't matter all that much that there's a record stock price, if companies are not going out and using the money they are making from stock shares to invest in their company, hire people, etc (which are things that help the economy). So something could be good for the economy, and not necessarily good for the stock market index. Here's a good article :
https://www.marketplace.org/2019/09/30/the-stock-market-is-not-the-economy/ . I like what they say, which is basically, the stock market is rich people betting about the economy.
Oil companies are large, highly valued members of the stock market(s). When their value falls (because they expect to lose income/demand/make less money/whatever), their PORTION of the stock market index (which tracks the value of the members of the index) falls. In Canada, they just suffered a 30% drop in stock value. Overall, the stock market is an average of the values of it's members. So when the price of one portion falls, the whole market, on average, may fall, unless the other portions make up for it. As of 2019, the energy industry made up about 16% of the value of the TSX. So... assuming the index had a value of 1000, and then something worth 16% (160) of it fell 30 % (1000-0.3*160 = 952 -> 952/1000 = wow, the market fell 5%!!! ( I may be slightly screwing up % change, and it's slightly more complicated, but I am tired)). And as a result, maybe other investors lose confidence, and sell their shares for less money, because, wow, the market has fallen 5% - and now the market's fallen 6%, 7%, etc... Is the economy negatively affected? No, not really, except....
In Canada low oil prices = expensive technologies like clean oil sands production aren't economically viable = projects cancelled = money not spent = people laid off/losing jobs = less money for consumers to buy things, which hurts the rest of the economy. Low oil prices also mean that clean tech companies are priced out of feasibility, too. Low oil prices also really hurt oil producing provinces tax revenue, as is being seen right now with some austerity measures going on in Alberta, which further affects consume spending, the housing market (another big market), etc.
Theoretically - the rest of the market could balance out these drops (which has been happening for the last few years, as oil prices fall). But only if the fundamentals for those other sectors are strong as well.
Meanwhile, stocks have been (imho) overvalued for years, priced with no reflection for the actual "Value" of the company and it's earnings (cough, Tesla, cough). Even before coronavirus hit, companies were reporting poor earnings forecasts, and yet their prices still continued to rise at incredible rates with no real reason. With coronavirus, people are expecting decreased consumer spending (coronavirus), travelling, etc. Several large companies (Samsung, etc) are going to have products delayed due to coronavirus closures. There will also probably be supply chain issues for several other products. China, one of the fastest growing parts of the world economy, is reporting 90% less than average car sales, and slaes of other things are down. And now large swaths of Europe are closing. The tourism industry is down, the car industry is down, the oil industry is down, the technology industry is down, and no one is willing to spend.
Suddenly, people start looking at the "valuation" of their portfolios, and questioning them. Which is dangerous in this confidence-based market where things are only worth as much as people are willing to pay for them.
Right now, the TSX / S and P Composite is at the same point it was a year ago or so. Which is also the same point it was in 2016. And we don't have much economic stimulus available (short of negative interest rates like parts of Europe) to prop it up, especially considering the US has been going on a tax cut and spending spree and didn't raise rates much after the LAST recession. Tax cuts and spending are typically drivers of recovery, but when they aren't available, recessions may last longer. A lot of the recent US tax cuts have resulted in corporate buy backs of stocks, rather than increased spending, which has artificially boosted the market without much of a resulting increase in spending, which would be a better "long term" basis for continued market growth.
Right now - we are at about Nov 2016, or January 2019 prices, depending how you care to look at it. Basically - we have been in a bubble for a while, and people are starting to realize the current crisis is likely to lead to long term impacts to profitability. The stock market only goes up until people are no longer confident in it, and then it falls... And that's what seems to be happening.
So, in summary - the market is a confidence scheme tied loosely to profitability of companies and also kinda sorta related to the economy, and only has value until people lose confidence, and could be messy, might be recover tomorrow, but... it's probably, as always, a good time to have a garden!!!