Sounds like your body went through a big withdrawal from your medication. You still had the medicine in your system, felt fine for two days. Over time the amount of medicine in your system got less and less. Your body, couldn't handle this big change and it sounds like had a major negative impact on you. I am glad it was just a panic attack, and you are safe now. It could have been worse.
cvb, what kind of support network do you have in your life? family/friends?
wishing you the best
take care