Overly worried.

Me and my boyfriend have a lot of sex. I was on the pill but i always forgot to take them so I stopped taking them all together. We stuck to condoms but they would always break. So I went to planned parenthood and got a plan b pill. They warned me that it may not work because I'm overweight and also I enetered my fertile window. Well my expected period is 3 days away and I feel nautious. I also have no appetite for food and I've had a lot of heartburn and I've never gotten heartburn in my life. Has anyone been trough this and have any advice for me?