penile problems, help

I sometimes need to urinate when i have a erection and this puts me off havin sex is this a normal thing?? also i have weak erections, even if im really turned on my erections just dont reach their full potential for long, i only feel they are about 70% of what they could be, what could have caused this and how can i resolve this problem? this has been goin on for 3years or more now and it really gets me down, i have no confidence anymore, i also have a anal fissure and i was wondering if this could have anything to do with it?? i also once masterbated and just before ejaculating i squeezed the bell of my penis as someone told me this could stop you from ejaculating, and it began to hurt really bad as the sperm couldnt get out and it felt like atearing feeling, maybe i have damaged something down there?? this was years ago wen i did that, i also had that same feelin a few months afterwards whilst recieving oral sex and it felt like my penis had been cut off as it went numb and felt like it wasnt there anymore, what could that have been? i also used to have pain in my lower stomach and grional area on the left side only but this does not seem to be a problem these days, and is it normal for my testicals to be loose while i have an erection?? please help.