Hypothyrioidism

Hello. Been ttc for 3 years. When I had my initial bloodwork done 2 years ago all my levels were normal. Shortly after that my husband was diagnosed with hypothyroidism/hashimoto's and he also has a brain tumor on his pituitary which increased his prolactin and lower his testosterone. All these issues have been resolved and his levels are normal. His SA is also normal actually great according to the doctor. My cycles have been very regular the last three years until my last one which was 21 days late. The doctor decided to re-test my thyroid and now also have hypothyroidism. My level was 4.9. I will get another blood draw in 3 months and go in for a check up. I'm just wondering if something similar has happened to anyone else where they were good and then weren't and got pregnant shortly after taking levothyroxine?

Thanks so much!