Leanna,
I think you're correct that your symptoms (dizziness, heart palpitations and headache) are all stress induced. To make yourself feel better, go to the doctor and get yourself checked out. Once you're cleared, know that it's only anxiety and it won't kill you.
I've had several bad panic attacks over the last 5 years, starting when my son was born. Usually 1 hospitalization a year, only to be cleared.
I've finally gotten to the point where I KNOW it's just anxiety. Not that it's not scary sometimes... or painful... but I KNOW it will pass. I'll admit there are time when I am 'hypervigilant' and check my pulse or am worried about some other illness, but the I've kept a journal since October and go back and read how many times I was "dying" and realize it all passed.
My last ER visit was in Sept... I've had @ 3 'bad' attacks since, but was able to breathe through them and calm myself down... no easy, but it can be done. If you need medication, even if it makes you sleepy, I would take it. At some point you'll find yourself controlling the symptoms better... it may take a couple of months... but as a friend told me, you didn't get this way overnight so the answer will take some time! Be patient and kind to yourself... getting control of the situation and getting better by working the plan is key.