I am getting mild abdominal pain with lower back pain; could this be herniated disc?

Hi guys,

I am a bit worried. I have been getting pain for a couple month in my lower back, but it's only been very mild pain. I started getting the pain after very heavy deadlifts at the gym, then the pain has been sporadic for that time.
I went for sprints on Sunday morning and then afterwards my lower back was really in pain. I felt sick and dizzy in the evening for about 2 mins, then it quickly passed.

However, since Sunday I have been experiencing mild abdominal pains in the mid abdomen area (near the belly button) and my bowel movement has changed as i haven't been going as regularly the last few days.
I am just curious as I haven't been to the doctors yet. I wanted to go and see the best doctor at my surgery, but unfortunately he isn't available until next tuesday. If it gets worse then I will definitely make an appointment with another doctor, but at the moment it isn't giving me too much problems, just the mild pain is all.

Has anyone experienced this before and could it be a slipped disc that is causing the stomach pain and lack of bowel movement? I had no problems before Sunday when I think I further injured my back.
Thanks.