Could I be pregnant? I have frequent urination, abdominal cramping, and gained 7pounds this week. I take birth control but do not use a condom.

May be. Needs to check pregnancy test first. Rarely you can get pregnant with ocp. Could have bladder infection and some times during ovulation you can have cramping and weight gain.
Pregnancy. If you take birth control pills it is unlikely that you are pregnant. Did you miss your period. You should see your doctor as you have frequent urination and abdominal pain. You dont gain 7 lbs in the early pregnany. If in doubt get the pregnancy test done as well.