Not sure what’s wrong with me

Have been going thru a pretty stressful time regarding family stuff, finals week and other general mental blocks. But the past 5 or so times i’ve had sex i’ve came almost instantly, (20 m) with multiple partners who i’ve been able to go 20+ minutes with before. Now I can barely go one as of late. I’ve tried researching methods, stretching before but they seem to have little effect. Not sure if it’s a mental or physical aspect but I’ve never had this issue before. It’s very confusing/embarrassing as someone who’s had a decent amount of sexual experience, any tips?