2nd trimester question...🤔

Today I am 23 weeks exactly. In my 1st trimester Everything was normal my nails my hair Everything and my hair got stronger so is my nails. Since the beginning of my 2nd trimester my nails are getting weaker my hair is falling (a lot) every day I comb my hair a handful of hair is in my comb. Am eating my vitamins everyday am eating healthy the baby is healthy everything is great....but is that normal? Is what happening to me normal? I heard that it was supposed to be the opposite like you have a healthy strong hair stronger nails you’re skin gets better and everything like changes to the better. So I was just wondering about it.

P.S : I have Hypothyroidism before I got pregnant i take 75mg from my medication. Is thats what effecting me?