I'm 19yrs old, I use to take birth control in December, '14 and before that, but ever since then, my period has always been 33days apart. I had to go to the dr recently because I felt sick, then they said my thyroid hormone levels were low, but my heart rate was at 140 and wouldnt come down, so I needed to do more testing, I don't have insurance to do it (it would cost over 1000$) so I don't know whats going on, but my dr acted like it would be very mild if there was a problem, but still serious. while on BC my periods were always 28days apart and about 3days, as of late they have been 33days apart and last 2days. I had my period the 4th, April, but not at all in May so far, I'm 5 days late now and have mild period-like cramps, with constipation, tiredness, a constant thirst, and my breasts have been getting bigger and sensitive. My bf and I have been using the pullout method and have sex pretty regularly. I took a test at 3days late, and it was negative, please help? I've never been late before.