If there is any chance you could be pregnant, an ectopic pregnancy
(where the baby starts to form in your Fallopian tube instead of the womb) could cause these pains, too, though they are usually somewhat severe. Eventually an ectopic pregnancy will cause the tube to burst causing severe pain and bleeding; this can be lifethreatening. If there is any chance of you being pregnant, you MUST see your doctor immediately.
I strongly urge you to see your doctor, Bran.