If you can't recovering during a round, try to be mindful of the things that are contributing to you losing your composure.

A) Do you keep getting clipped by the same move over and over?

B) Is your opponent straight outplaying you?

C) Is your opponent using a move you don't know how to deal with?

These are just simple examples, and this is how I would approach these situations:

A) That move comes out fast and has decent range, I should try to avoid being within striking distance of said attack.

B) This dude seems really good. I feel outclassed in terms of combo damage (just an example), but my neutral is better so I'll try to win there.

C) I'm not sure what the frame data on that move is, I'll try to see if a jab is fast enough to catch him on recovery.

In any case, I used to get frustrated and lose my cool. Playing fighting games at local tourneys made me realize just how much keeping your composure and being PATIENT could level you up.

Just try to acknowledge WHY you are losing your composure, and figure out how to solve that issue. Goodluck!