16! am I most likely pregnant?

Okay so it says that ovulation begins around ten days after your period ends. My period ended Wednesday March 7th, and exactly ten days later on Saturday, March 17th I had unprotected sex. My period is due in about 3 to 7 days. It says online that spotting can occur between 3-5 days after the day of unprotected sex, and this would be called the 'implantation bleeding'. I experienced a light pinkish brown spotting 4 days after the unprotected sex on Wednesday, March 21. It's now Monday, March 26th and I have tender breasts and cramps that feel sort of like menstrual cramps, but not as intense. I spotted a little bit after sex saturday March 24th, just a couple drops. And haven't expierenced any more than the two days I've just wrote about. I feel like I'm making more stops to the bathroom, but that could just me being paranoid. I'm sixteen, and don't really have anybody to talk about this to right now, so any help and advice would be greatly appreciated! And trust me, after this, I will be using condoms! So please don't tell me that. I need real comments on what you think is going on. Thank you so much!