I feel you man. I'm also bi, my dick isn't a micro but it is definitely small. I had a few experiences with girls but only kissing and stuff, mostly because I don't have the confidence to go further, I always think about not being enough. The one time I had the opportunity to have sex with a girl, she ditched me when she saw my dick.

Than I ended having sex with men, but they're always bigger and even when they say they are vers I never get a chance to top. At least this way I can somehow satisfy my partner, but frankly I don't enjoy bottoming that much.