Feeling like I can't catch a break

I'm really stressed, to say the least. I just started my senior year of high school and I'm dealing with a lot of issues that I don't know how to handle. First of all, I have (and have had for about 12 years) pretty bad anxiety. I have awful acne as well, and not just on my face, all over my body. My teeth are a mess (I have a condition that makes them break and decay VERY easily) and I'm almost constantly in pain (like a 6/10 on the pain scale) and it makes me extremely irritated, especially at school. I just feel so overwhelmed and like I can't catch a break, I just want everything to go away and I don't want to be in pain anymore. I know it could be worse, I could have cancer or be dying, so I feel bad even saying this. Has anyone else ever felt like this, how do you manage it?