I went to a festival this past weekend and it was very hot. From Thrusday to Sunday me and my friends walked a LOT in the festival and around the town and campgrounds that we stayed at. I was over heated and sweaty for 3 days straight, day and night (we slept in a tent). I take birth control (Lo Loestrin Fe) and the last four days of the pack are the time where you're supposed to have your period. I started taking birth control pills in February and I've had my period while I wasn't even one the period pills (so it's been kind of irregular). My first period pill this month was yesterday and I haven't gotten my period yet. I'm very nervous. Could the reason be the extensive amount of time I spent in the heat and the absurd amount of walking I did this weekend?