I am 18 and had sex for the first time a couple of weeks ago two nights in a row. We used a condom both times and checked for breaks, even going as far as pouring water into the used condom to be sure. We found no leakage, but I am a day late for my usually regular period. I use a period planning app and we were intimate on days that were projected as fertile for me, but the only way I would have had vaginal contact with semen is if the condom broke. We never once went in without one or got his penis close to my vagina when he had preejaculate. I had my normal PMS symptoms earlier last week such as increased appetite, mood swings, and mild cramps, but have yet to start. There was a slight tenderness of my nipples which is pretty uncommon for me, though it is a period symptom for some. I have been peeing frequently, but I think it's because I'm really on edge and continuously checking for any sight of blood. My breasts feel a little bigger, but I could also be psyching myself out; I am very paranoid and worried. I was not on any birth control and I don't plan to have sex again until I am, due to the stressful and worrying fear of not knowing like now. I was very stressed due to finals at the beginning of the month, and my last period carried over into this month a day or two longer than usual. It was also a heavier and longer period than usual in general. I've researched a lot and know I am most likely late due to the fact that I'm stressing and worrying about it so much, but I would like some advice to help put me at ease. I know I'm not very late yet, but I'm just very scared because I don't know how I could cope with a pregnancy at this time in my life. When should I worry enough to take a test and how many should I take to be sure that I'm ok?