Lately, i literally last under 30 seconds
This might be something that just fixes itself. How old are you, and is this something that just happens with sex, or also with masturbation?
I'm 30, it's got worse over the last few years, the more I think about it the worse it has become... it happens when masterbating but not as bad..
Getting drunk used to stop it happening but that doesn't work anymore.
I thought you were going to say you were a lot younger, but if you're 30, then I think you should see a doctor about it, as there are various treaatments available. It's possible that you may have "frenulum breve" btw, which can also cause problems, but which can be corrected by steroid creams or frenuloplasty.
These links may help:
https://patient.info/health/premature-ejaculation-leaflet
https://patient.info/doctor/premature-ejaculation-pro (written for doctors)
If it helps, one of my exes said her best ever lover (so presumably better than me :[ ) was a boyfriend who couldn't last longer than 30 seconds, but made up for it with extended foreplay.