Thyroid Disease and Menstrual Cycle

If you have thyroid disease, I'll bet at one time or another, or for an ongoing amount of time, your menstrual cycle was a bit whacked unless they were managing your thyroid disease correctly.  Mine has gone from being 45-50 days apart, to every 30 days but really heavy and painful, to every two weeks, and now - I'm five days late beyond the 30 days so I'm not sure if my menstrual cycle is getting longer again or if I'm pregnant (yes, I said pregnant). 

I shouldn't be pregnant.  Birth control has been used 100% but things happen.  It would be a huge shock if it did for me and my husband...oh wow, he'd probably fall right over.  With my thyroid disease, I don't know if I should wait this out and see if it's just my thyroid or buy a pregnancy test. 

I'll put it off a few more days.  I have too much to do anyway to worry too much at this point.  I have to get sponsors for my daughter's cheerleading squad, look up car insurance quotes at carinsurancelist.com, and chauffeur my kids around over the next couple days to their various activities. Besides, if I buy a pregnancy test and it's positive, that means we'll have to go into complete shock that much earlier!