Depending on which antidepressant/antianxiety medications you've been put on, a lot of times, the side affect is constipation. (it ***** yes I know)
Also, stress and anxiety can cause problems with your digestive system too. You've got to get yourself on an eating schedule. Make sure that you are eating foods that are good for your digestive help (perhaps even start on a probiotic to help). The build up of toxins from the waste that isn't going out of your body is cause the crummy feelings and the gas pains and cramping. I would seriously suggest probiotics and even a fiber supplement to assist getting things back to normal.
I hope that you feel better soon.
~Michi
Btw, I haven't had dairy in a month.