erection issue

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.

Workout, eat a healthy diet, cut back on alcohol and don't do drugs. Practice safe sex.

Tip: sex is never consistent, and is different with each partner.

Having anxiety about your performance can be another factor.

Communication with your partner is key. If something isn't working for you tell them you want to try something different.

Relax and enjoy the experience.

Given tips are fine for you mate you should definitely bother them because they can help you a lot,That is nothing to be worried about,Avoid depression and stuff all you need to is stop that for a while and concentrate on wellness.