It sounds like you have already seen your doctor
if you have had some blood work done, and it is good to hear that that is normal. It is true that rapid hair loss
can sometimes be associated with thyroid problems or anemia.
Assuming there is no scarring or inflammation of the scalp, then the next most likely possibility for explaining your hair loss is something called telogen effluvium. This is a thinning of the hair that occurs uniformly over the entire scalp and that is usually precipitated by a shock to the system - for example, a serious infection or medical illness, psychological stress, a new medication, etc. Therefore it is worth thinking about if there has been something like that in the recent past. I am not sure why you are losing weight - is this intentional? If not, or if you are not overweight, there may be an illness underlying this or poor nutrition, which could trigger telogen effluvium.
Also, I suspect that discontinuing your birth control pill may be related to the acne. There are some types of birth control pills that improve acne a lot, and so coming off this pill may have worsened your skin.
Talk to your primary care doctor
for more ideas. Good luck.