Period accidents

Sa

So when I was a teenager I NEVER bled through my pants but now that I’m 20 I always do. I bled through yesterday at school and I just got to school this morning and I bled through. I have no idea why, I’ve been using the same pads forever and they’re great but for some reason it keeps leaking through the back of the pad and I’m getting so tired of it. I feel like nobody else has this much trouble. I literally have to wear two pads 🙄