I suggest you buy back your BTC now before prices shoot back up, because the logarithmic rainbow charts are already putting this current price in "Basically a fire sale", even almost breaking below that color line - meaning we will never see $17K again (sorry Bitcoin to zero doomers).
I wouldn't be in a haste to go in if I were the OP. I will wait for today to pass because I believe there will be a correction downside to what price did by tomorrow or so. OP shouldn't be in a hurry to trigger a buy trade. Just relax and watch paint dry.
There is some confusion about what you actually did, according to the title you shorted the bitcoin at $17k, however, in the post you state you sold it at $18k.
OP sold at $18,000 and made some gain but felt that Bitcoin was going to crash and then they sold/shorted it at $17,000 hoping it would hit $15k or lower, only for Bitcoin to zoom pass $18k and even $19k now. That's what I garnered from what OP narrated.