Balance went down $7 after swapping coins

Hello, I am new to cryptocurrency so please bare with me. Yesterday I decided to swap two of my coins to BNB. When I went into the app, my balance was at $40. I proceeded to swap all of my TKO and ZEP into BNB using pancake swap at 11% slippage but when I looked at my balance, it went down to $33. Now I know $7 loss is not a lot but I am pretty confused as to why that would happen and would like to avoid this problem in the future. I checked all my transactions and the fees were only a couple cents so should not have resulted in $7 loss due to transaction fees. I also had someone experienced with trading look through my trust wallet to see what the problem could be and he could not find anything that I have done wrong on my side to result in $7 loss. I tried to re import my wallet but that did not change the balance. Don’t have another device to test out either. Also want to mention that two other people I know, swapped the same coins to BNB yesterday, the same way I did, but their wallet balance stayed the same. Any help is much appreciated, thanks in advance.

I had the
Same issue when I sent from Binance £70 I only received £43 in my wallet

Oh no! Hopefully someone can help us out because it does not seem right… Worried about doing any future swaps now as I do not want to loose more money.