Sounds very complex..

Autoimmune issues typically go into remission during pregnancy, because all the hormones go up and especially cortisol, you see improvements in things like MS and Rhematoid arthritis etc.

Then when the pregnancy is over--- boom... it all comes back.

However, many of your symptoms sound like low thyroid to me.
The Cold intolerance, tingling, PN symptoms, etc.

Also there is a condition called carcinoid, which is an elevation of serotonin in the body secreted by tumors in the GI tract. It causes episodes of diarrhea, and tingling flushing of the skin.
Doctors can test for this if they think of it...because it is considered "rare".