first late period in a long time

Now this period app just moves your period to the next week until you have it and that's what it's been doing. I was suppose to start in the 17 and I am always watching for it cause it can be irregular and maybecome thatvweekend or the week after. Now why am I stressing cause this has happened before? Yes I had sex on the 12th actually. Not knowing I was ovulating that day I know I know stupid but I wasn't Worried. It had been 4 months since I had sex and when we have sex I make sure that the condoms are new,not expired,no holes,plenty enough room at tip,was opend with my hands,put on before sexy time and is bought with spermicide that comes with the condoms lube. When he's about done he will not finished in side and pulls out but dose not remove the condom till he is done and he never puts it around my virgina.When he is done he removes the condom in the bathroom away from me and I then wash myself after. Now what stresss me out worse is I was suppose to start my birth control this month cause I have bad pain during my period. And my mother has been asking me every week if I have started and is now treating me like I'm a pice of dirt because I am late.(my mom doesn't know I am sexually active we aren't that close and she's not very understanding about those kinds of things. I am also 18 btw so she assumes that I am). I was nervous about birth control and the missed period has made me stress and I just want to know what you ladies think. I've had all my normal pms symptoms. What do you think? This is my 44th cycle day the lastest I've gone is 43. Help? And yes I'm thinking about taking a test even tho it's a scary thought. And my boyfriend and I are done having sex for a very long time cause of the stress this has caused both of us