Advice on what to do?

I keep having pressure on my bladder for the past few weeks. It isn't a UTI because I've been tested twice and it's negative. I'm 90% sure I'm not pregnant because I've never had sexual intercourse, but I have done anal and oral (received and gave). I feel bloated, my stomach is slightly sticking out more than normal and when I press it, I just feel pain and the need to urinate. Could this be an STD? Or a more serious bladder infection? Because my back hurts a bit, too. My partner does not have any past sexual partners, and he doesn't get cold sores and didn't have any cuts of any kind in his mouth when giving me oral. When we did anal (we've only done it ONCE) it was with a condom, which did not break. What do I do? I don't want my parents to find out if I may have an STD. Is there any way I can get confidentiality? I'm 17 years old. Please keep negative comments to yourself. Thank you to anyone who gives me feedback! It means a lot, I'm really worried about my health right now.