I just saw the market, it turns out that the bitcoin price has gone up.
and I feel very happy with the increase in the price of btc, and I bought btc at a price of 17000 and I just saw the market now the price of bitcoin is 22000.
but do you think I should sell it, or keep it?
I think that's left for you to decide yourself, if you are satisfied with the profit you have made and you think these is the highest bitcoin can go then you can sell, but if you believe that bitcoin price is still low then you should hold.
because I'm afraid the btc price will drop again to 17000,
Because bitcoin price went up a little bit those not mean it won't still dump to $17k or below, nobody knows bitcoin movement, but if you are planning to hold, then you shouldn't be disturbed if bitcoin price dump below the price you bought it.
You might sell your bitcoin now, and you will be waiting for bitcoin to dump so that you will enter again, but you might not see bitcoin at that price again, if you are having bitcoin already, just forget about the price movement and hold, stop checking your wallet frequently.