I am not quite in your situation as I could not get pregnant (blocked fallopian tubes) but found out I have Grave's disease after getting tests done by my reproductive endo which led me to a regular endo.
I will be doing in-vitro fertilization and all my drs' told me (my endo, reproductive endo & gyno) that my throid levels need to be in a good place in order to conceive as having the hyperthyroidism increases my chances of a miscarriage. I'm sure part of their concern was also the $ I would be spending on IVF so they want me to be in the best possible health.
I have been on a very low dose of PTU (50 mg a day). I just had my levels tested after being on the drug for 6 weeks and my levels are now normal. I am hoping I can move ahead with IVF, but still need t ochek with my drs.
You may want to get your thyroid levels checked again, especially if your periods are irregular.
Good luck to you.