I literally have no solution.

I (15m) am currently a student in secondary school and honestly, I don't know how much worse this can get. I have so many problems in my life right now that affect me just as much as IBS and I'm sorting them out right now, and they will probably be solved in the next few weeks but.. I don't know what to do with IBS I get so stressed. It's 4 months until my GCSEs and I sorta have an addiction to studying. To the point I have probably a meal worth of snacks in the evening after dinner (usually what my auntie cooks) and then I starve during the day because I'm afraid of needing to go in school. I've had at least 5 accidents in school, one on a plane (yeah..) and basically 20 accidents in public *not even exaggerating, i'm kinda counting. My anxiety is so hard to solve right now and people keep saying to me 'just eat and relax' but I can't when my auntie expects good grades, me to constantly be doing housework and doing things she wants me to do. I went to the doctors 2 years ago (my auntie knows about my condition btw) and it didn't really do anything. He said it was stress but.. I didnt tell him everything that was going on. I've basically discussed my problems with everyone who could help me but I feel like I'm repeating myself, or that it's useless because they only care when they have to wait outside the toilets as I clean up. I'm planning to get a toilet pass, but again when I have exams, and classes it's just. Relieving my body and meaning I miss out. It doesn't treat my body. Breakfast and lunch = impossible Sometimes I even hide the fact I eat lunch after school (1 hour before dinner, btw. I am starving and idk what to do) Then sugar and coffee in the night which usually leaves me the next morning. The same cycle over and over. And even water.. one drop genuinely makes me terrified. I'm losing so much weight though. I was in bed with 3 layers on (I even do this during Summer, it's strange). Last time i checked, i'm 175cm and about 52kg. I'm surprised my girlfriend even wants me atp. I only relax or try to stay calm when my auntie forces me to go on a car trip. (Which we are today 😬) I guess there's really nowhere to go there. Otherwise I don't handle it because I don't really need to. We have assemblies, classes we aren't really allowed to leave and exams, well. I'm gonna have to really convince my headteacher to get me a toilet pass, even without the doctor note because there's not many around here and my auntie won't take me again.

Does anyone know how I can start eating again? Or how to leave the house without fear, even if i'm going to the corner shop? Or how to live? I have sixth form next year. I can't let this slide. I need my life back because it's been too long now