Why am I struggling to breathe all of a sudden?

About four weeks ago now I started struggling to breathe. My uncle died unexpectedly a week ago of a brain hemorrhage but I don't think its because of that because I had trouble breathing long before that happened. Four months ago I was diagnosed with Hyperthyroidism (one part Graves Disease). I'm on medication for it, do you think it might be that? I dont think so because I've only recently had trouble breathing, if it was because of my thyroid condition I would have had a breathing issue back then, not now all of a sudden. I keep telling my mum about it, and lately it's gotten harder to breathe. I dont think she even believes me, she sometimes even ignores me when I'm clearly struggling for breath. What is wrong?? It's really annoying the crap out of me.