What Causes Nausea,fatigue,bloating And Lower Abdominal Cramping?

I'm not sure if I'm pregnant or not. I had a tubal ligation 12 years ago and still getting my menstrual cycle. I have been experiencing some bloating with lower abd cramping and some pain on the left side that comes and goes and at night when I'm at work I feel what seems like fetal movement or gas? I also have some nausea and fatigue, but I haven't taken a pregnancy test because of the tubal ligation and still getting my menstrual. I'm not sure if this is just gas or something else.