I'm an 18 year old female. For the past month or so, I have been feeling extremely tired, and I get really dizzy. At first, I thought it was that I wasn't getting enough sleep, but I started to get a lot more sleep, and I feel a little better, but still really strange. I sleep for about 10 hours, and I still feel exhausted, especially upon waking up, and I lack the motivation to get out of bed or and lack the motivation to exercise; all I feel like doing is sitting on the couch. When I stand up, I get dizzy, and I can feel my pulse racing. I can feel my pulse racing through my veins, and it scares me. I also get stomach cramps, and my throat is really dry. I've also become moody and irritable. I feel angry most of the time, for really no reason or for things in my past that I haven't thought of in years. If someone upsets me, I lash out, whereas in the past, I generally wouldn't have. I know it's not PMS because it has been going on for a while now. I feel really silly asking about this, but it's bothering me, and I don't know who to ask.