Hair is falling out ... again

So I've noticed that my hair is thinning again, and I was wondering what this typically means in terms of my thyroid. I've had this happen before. Once when I was in my first trimester of pregnancy, and once when I was 9 months postpartum and weaning off of breastfeeding. Both times I assumed the hairloss was hormonal, but later I developed a goiter that never went away. (7 years now) So now I am once again postpartum and breastfeeding, and its about 6 mos in.. I've been having strange symptoms, most likely autoimmune (blood work only shows sjogrens flare up though) an I'm wondering if this might be related to hashimotos o if it is just homonal stuff related to childbirth..

Any advice is appreciated.

Your body goes through a tremendous amount hormonally after childbirth. I always said it took a good twelve months after each of my kids to feel somewhat "normal" again.
Also, breastfeeding takes a huge toll on your body. All that work it's doing to produce milk.
Are you eating a good nutritionally balanced diet?
Did they test your iron levels, vitamin B12, zinc? Did they also test all your female hormones?
Remember that the state of your hair NOW is due to whatever your body was going through approximately three months ago, due to it's growth, shedding cycle. I bet that three months ago you were probably suffering from lack of sleep at the very least?
It can be frustrating trying to work out why hair thins but I'd say it's likely to be a combination of both hashi's and female hormones since they can so often be closely linked.
Are you able to take evening primrose oil while breastfeeding I wonder? It's supposed to be very beneficial for hair loss. But please check first.