Help with always going backwards

Disclaimer: I train MMA but the answer I’m looking for can still be found here: when I spar in standup, aggressive opponents, (especially good 1s) I feel like when I try to fight on the inside I get touched up, and when I’m at range they blits forward and I get touched up. I try to back up fast and throw jabs and lead hooks which end up pretty weak because Im basically running backwards. I do try to circle a little, (usually towards my right, I’m othodox) after the initial backing up, but I’m not crazy fast and don’t have good stamina so eventually they catch up and I just cover up while backing up and still get hit. I have this habit I feel like I can’t break. I alot of times run into others in the gym when facing aggressive opponents. I’ve tried to run less but it ends up feeling like a dangd if ya do dangd if ya don’t. I do notice when I get tired I stand a little tall/straight legged, and I think also when I “run” backwards I do this. Part of it is because it feels like I move on my feet faster with straight legs but it also seems to take less energy when I’m tired but it likely makes me throw weaker shots. I’ve trained for a little over a year. When I do a tit for tat type of spar where we the other person isn’t constantly aggressive, I do much better but with aggressive opponents, even new people, i don’t have much success. Any tips are helpful!