Why haven't I got my period yet? Help!

I used to take birth control for 2 years straight and then I stopped 2 months ago because my period was having horrible cramps and it didn't seem like the birth control was that effective anymore. After half a month of being off birth control, I started a new one. 3 days after starting the new pill, I had unprotected sex. I was scared because I didn't know if the birth control was affective yet. I took the morning after pill just in case. I was still taking my birth control regularly and had unprotected sex a couple of more times. After my first month of birth control was done, I stopped it because it was causing me to have insomnia. During that first month on birth control, I was spotting for a couple of days and I didn't know if it was my period or not because it was so faint and light. I didn't think anything of it. On the last day of the spotting since it was barely there, I had sex. I was still on the birth control. Now a month has gone by and my period is 2 weeks late. I know this is a very confusing story but I am stressing out a lot and I keep thinking I'm pregnant. Why haven't I got my period yet? Is it because I only took birth control for a month?