I can barely breathe; what's wrong?

I'm a thirteen year old girl, just saying that if it has any relevance to what I'm asking. So I went for a cleaning at my dentist; they brushed my teeth, did the whole routine. At the end, they gave me a fluoride rinse that I had to swish in my mouth for a minute. The dentist told me to make sure NOT to swallow it, and I didn't swallow any. After wards, I spat it out but had a horrible taste left in my mouth. I forgot that you were supposed to wait to eat or drink, and I had a sip of water after about ten minutes. I went out for dinner and had a sandwich & iced coffee. During my dinner I felt really weak and nauseous; I could barely get up. My dad drove me home and when I got home, I went to lie down and relax. I was fine for a little while, but then I started to get sharp pains right above my collarbone area. My airways close up and I couldn't breathe for about 3 seconds. This process repeated every few minutes, and I just felt really weak. I took some Maalox for heartburn, and it's not as bad, but I just want to know if there is anything I can do to help my situation? I feel really tired and worn out, with no appetite. Any thoughts are greatly appreciated.