For one man's view on current financial markets risks, you might want to read a comparatively short article titled How Worried Should You Be About the Stock Market. In summary it says that one ought to be worried in the short term, but not in the long term. The author also says:
"Anyone who cannot afford a decline because they have a near term need for their capital should realize they are risking losses in stocks. They always are"; and,
"What is most important: in order to time markets well once, you have to be right twice. First, knowing when to get out, and then knowing when to get back in".
Financial market returns tend to be comparatively very low today at a time world economic risks seem very high. I suggest you read the referenced article and reach your own conclusion with respect to 'how worried you should be' after consider that:
risk and reward are 'siamese twinned'; and,
'timing the markets' is a very difficult thing to do.