Irregular Period

I have a very irregular period from last 1 year... last year I had 3 months continuous spotting then no periods for 3 months then spotting for 3 months then when I took provera I had normal period since last 2 months and no period so far since March. I am TTC from last 8 months. All test come normal, but my gyno said that my thyroid level is low 7.0 right now. She is just changing medicines from last 6 months. Sometimes the thyroid gets low and sometime high. I dont know what should I do to make my period regular and to conceive naturally. So much depressed now. I will be 31 next month but really desperate to have a baby now. Any suggestions.