Please read. need some kind of positivity right now

So I did not get my shot last August. I then got my first period in November, skipped December. But then in January and Feb my periods were the exact same length, exactly 1 month apart. I thought this was a good sign that I was back to normal. But then today I woke up with cramps and brown bleeding. Took a test and was negative. Is there any chance at all just because of the bleeding I could still be pregnant? Please help. I'm feeling so discouraged at this point.