Late period. Advice??

Al
Need some advice and wondering if there's any real reason to worry. I had sex 2 months ago. We used a condom but were drunk and weren't too sure if there were any rips. He didn't cum at all and wasnt that close to it. This was the day before I was planned to ovulate but I did decide to take plan b 36 hours later. I received both "periods" in the last 2 months. They were a little lighter and shorter than usual (I did have to use tampons). I was expecting my period on the 1st of this month but it never came so I am now 3 days late. I have some cramping every now and then and my boobs are a little sore and I feel a little bloated so hopefully it's a sign my period is still on its way. I took a pregnancy test just to make sure and it was negative. Do I have any real reason to worry?