Advice please!

My boyfriend and I vary between condoms and "pulling out" (I know not always reliable) but he has not cum inside me ever. I was bleeding about a week ago, I don't know if I would call it spotting because I had to wear tampons for a day and a half due to the heaviness of it, and it freaked me out. At the time I was supposed to be ovulating I had a UTI and a severe sinus infection and was on HEAVY antibiotics for over a week, I know I've read that infections can affect your cycle but I'm still paranoid that I might be pregnant. I took an early response test this weekend and it was negative, and I don't really have symptoms (no dizziness, sore boobs, constipation, increased appetite or fatigue) but I'm  still getting myself all worked up. I know stressing can delay your period even farther but has this ever happened to anyone else/any thoughts?!