It is possible that, even with a profit, you may have the perception that your balance has decreased.
Keep in mind that on Binance:
- The total balance in BTC considers the sum of all coins and fluctuates with their price and BTC itself
- The balance of parities (quote assets) like BTC and USDT will decrease whenever some amount is allocated in a trade
- In Futures, PnL results are unreliable (see Binance's own disclaimer)