Having signs of pregnancy and l ultrasound shows follicle in right fallopian tube, is this possible?

I went off of birth control on 3/26 (first day of last period) and was fine until 4/9 and have had non stop lower abdominal pain for 6 days since, along with some other pregnancy symptoms. I could possibly be 1 to 1.5 weeks pregnant, but all urine tests are showing up negative since it is too early. I had a l ultrasound today, which ruled out anything bad and showed a follicle in my right fallopian tube. The tech said I probably ovulated a week ago and the pain was from ovulation and I'm not pregnant....but could I still possibly be pregnant since it is too early to see anything on ultrasound? I've never had signs like this before even years ago when I came off of birth control. Thanks!