Now know that I felt particularly awful because of a throat infection (I don't know if it's connected to the thyroid or not, but I don't expect it was). I've recovered well from that without antibiotics.
The L-Thyroxine seems fine i.e. no side-effects at all. The beta-blockers and calcium-channel-blockers are doing their work nicely, so now it's a waiting game to see if and when the thyroxine will cure my BP and panic problems, along with the other more typical hypo symptoms.
Feeling positive I'm on the right meds :-)
Thyroid Disorder Tracker