Any ideas please?

I find it really hard to talk about things with people so I'm just going to throw myself out there. 

I needed to pee quite badly today in class so I waited for the bell to ring and I went to the bathroom but my bladder area was hard and hurt quite a bit and I thought after going to the toilet it would go back to normal but it didn't and continued to hurt for the rest of the day and it made me feel like I had quite a lot of pressure on my bladder and needed the loo but I actually didn't. It's happened a couple times and it's quite uncomfortable. Is it just bloating? Any ideas, suggestions? Does anyone else feel like this?

If this post offends anyone I'll take it down as soon as I can. Xox