Am I experiencing postpartum thryroid problems?

I am 3 mos. postpartum, and have all of sudden started experiencing heart palpatations, sensitivity to heat, hair loss, perspiration, and fatigue. I am normaly very healthy, no pre-existing med problems, nod meds, etc. I get plenty of sleep b/c baby pretty much sleeps through the night already. I did have a rather difficult delivery, but it was a very short labor.