Someone explain to me or give me a reason why this is happening to me:

I buy with 7.03$ with #btc being at $70,250.

I proceed to sell the "7.03$" of #btc this reaching a price of 70,313$.

My account statement was at 7.92$ before trading, I proceed to check and I get 7.92 #usdt !!

Can someone explain to me what I'm doing wrong? Several trades made for good value arrived and I don't see my account statement going up!!!