1. Does this means I am paying extra fees.......first I paid for converting BNB to USDT, then while swaping I again paid fees to ROUTE USDT - BNB - My TOken
Yes, you can see it on the confirm page that there is a fee before you confirm the swap, if nothing shows then there's no fee for the swap of the particular token/coin on BSC.
1. Should I stop this converting BNB to USDT.
If your purpose is just to check the usd price of the swap, and if it matters to you the cents for fee, then better stop.
2. Is there any way to calculate and to know , while swaping BNB to My TOken what USDT price I am paying for that token?
AFAIK there's an automatic computation in the swap page every time you change the number in the "You Pay", the "You Get" will give you a hint on how much you will get and check the conversion of the token to usd in coinmarketcap (their converter is in the lower left side in desktop mode) website as trustwallet uses cmc for their pricing conversion.
Where Does Trust Wallet Get Coin Pricing Data From?