We cannot predict the future and anyone who tells you something is guaranteed to happen is someone I wouldn't listen to but we can use the past to help us make better decisions, moving forward.
So much fear everywhere it's sad to see but that's the way people are. In my opinion, if you feel terrible or stressed out, you invested money you shouldn't have.
A simple rule I use is I invest money I am willing to lose. When I buy a stock, I part with that money and believe there's a chance I'll never see that money again. Now, common sense will tell you the SP500 will never go to $0 but for emotional purposes, I take this approach.
I go over my finances and make sure I won't need the money I invest if a worst case scenario were to happen. Once you do that, you no longer are emotionally tied to that money and can make good decisions.
The good part: time is on your side. The more time that passes the more gains, you'll eventually have. After 5/10/15 years (different every time), you'll have 50%+ gains and once you get there, even if 2008 happens, all youre losing is your gains.
How will this help you now? It won't. But it can help you moving forward.
If you are feeling stressed/panic/fear, then you were greedy and invested more than you should have. Greed is a terrible thing and will ruin you.
Educate yourselves. Great thing about the internet is it's a free tool to learn.