I got into the bitcoin again last year after losing all my 4.5 bitcoins to ponzi schemes early last year. I bought in bitcoin again at $20k. Now bitcoin is $6k+. I'm regretting my actions. 
Would you have regretted your actions if you bought in at $200? That's the gamble with investing. You can either cut your loses or if you believe in bitcoin long term then keep holding in the hope that bitcoin will once again reach 20k. Nothing is guaranteed though and maybe it will never get back there, but many people are optimistic.
Out of interest, how much did you invest? If you bought a small amount then there's probably not much you lost but if you bought multiple coins at $20k then that's a different matter.