i am facing erection issue,don't get second erection and ejaculate prematurely

i am 23year old,i am bi sexual

its been a while since i had sex with a girl,its actually alot easier to find boys willing for sex here than girls.

sex with guys scenario:

anyways now the issue is that i do get erection but if i continue to do orals for sometime,i loose erection and it doesnt comes back and i feel really embarassed or sometimes its like i have penetrated inside but now if i take it out for some other position,it will loose erection and again i face hard time getting it back though i noticed if i rub it on ass then it eventually gets hard,i am just 23,what is wrong with me?

also once i have ejaculated,now if i want to do it for second time,it gets semi hard but i dont get full erection,now if i am alone and i try,it does gets hard,but if am with some one,now i will try to get erection for second time,it simply wont get hard,i dont know why

this makes me very embarassed,what can i do?i have been searching alot on google,but then i thought to ask my question directly

also is there anyway to make my penis any longer safely?

actually i think the issue started when some one few years back gave me some erectile dysfunction tablets saying it will increase your stamina alot,ever since i tried those i started facing these issues though i stopped taking those pills after sometime

i never had any viagra or anything

also whenever i put my penis inside ass,i get very hot and after only a few jerks i ejaculate,is there anyway to increase my timing?

please help me on my issues,thanks.