I think I have a bladder infection?

I'm 14 and I'm pretty sure I have a bladder infection but I'm not positive. I've looked up symptoms online and I think I do. Since yesterfay evening it seems like I have to pee all the time. And then when I go, barely anything comes out most of the time. Then afterwards, I have sharp pains in my pelvic area, or pressure. I feel uncomfortable in any other position than laying or sitting down. I've been drinking cranberry juice but I can barely down it. Because I feel like I need to pee right after I drink it, and I get queasy. I'm very queasish around blood and sickness and gross stuff so I can barely down the juice at the thought of having a bladder infection. Please help! My mom gets them sometimes and I think she may have medication.