I agree that it was probably because your starting dose was too high. How much were you taking?
Have you ever had tachycardia before?
The same thing happened to me and whenever my Endo tried to put me on a higher dose, I would get chest pains and angina symptoms. It is indeed very scary. My endo has had to very very slowly increase my dose, but even what he did wasn't enough.
What dose did they put you on? Maybe they put you on too high a dose to begin with. I have heard some doctors start people on .50mcg, but usually they are supposed to start at .25mcg and then if tolerated, go up to .50mcg and so on. I couldn't do that since I kept getting angina even on .25mcg, so now I just increase by quarters every couple of months. There is a person on this forum called goolara who went through the same thing, and she will i'm sure answer your post too and tell you how she managed by using a pill cutter and just increased in quarters and it helped her a lot. Good luck, I hope this helps you. I know how it feels to be in that situation. I'm still not well, because it's going to take me a long time to increase to where my body wants to be to feel better, but every one is different, so maybe it won't take you as long. One thing in your favor is you are young yet--only 37. I'm 63 so I'm sure it has some effect on why I'm still not well. Plus, I have Hashimotos which is an auto immune condition, and I could be getting more than one auto immune problem, so it's going to be a long haul for me.
Take care and let us know how you are doing.