What do you think will happen tomorrow with the BTC (up or down?) if the stock markets worldwide crash again?
I am afraid that the BTC will then go towards 3k or even less. The altcoins will hit it even harder.
I dont know what i should do today, sell all my altcoins?
To be honest if you have that mentality, you shouldn't have invested in the first place when know that Bitcoin is this volatile and risky. What I suggest to you is to relax for a minute, don't involve yourself with cryptocurrency for a month, and just HOLD. Why are you rushing? 2008 stock market and 2018 cryptocurrency have seen worst and we still rose from the bottom.