Struggling with Emotional Regulation

Hey. I have a problem. I found something at a garage sale today that I really liked, and I didn't have enough money for it. I ended up throwing a temper tantrum when I got back in the car and it had felt like something was controlling me inside. It brought negative flashbacks of the incidents that I had when I was 8 or 9 or 10. I'm almost 21 and this is the first, like real temper tantrum I've had in years. My question is, could that be anxiety driven, or maybe a hormonal imbalance, or what? I've been dealing with stress all week. I quit my job on Wednesday because I wasn't getting the help I needed, plus I had a panic attack on top. I had a panic attack again Monday night and ended up missing my 8:00 class in the morning because I slept too late. I have a lot more other things coming up in the next week here, including the Special Olympics bowling season starting tomorrow (Sunday) and my birthday on Monday, and then something extra special Tuesday because it's my friend's birthday (he's a famous inventor, so he's got something big going on), and so forth. I am working on getting my medications adjusted again as well, which includes Duloxetine and Propranolol and Paliperidone and stuff like that. I've been taking my anxiety pill (Zyprexa / Olanzapine) every day to keep me sane, but sometimes the anxiety takes over. Plus, the way my mental health is right now, which I'll tell you is shit right now, that doesn't help anything either.