Stomach pains, bowel changes, decrease in milk supply

So on Saturday night I started having severe stomach cramps that woke me all night; the pain was similar to that of food poisoning.  I felt nauseous but didn't vomit and had no appetite.  Ginger Ale seemed to help.  
Sunday morning I continued with cramps and nausea, but no major changes, I had a normal bowel movement - the cramps weren't quite as painful, still no appetite.  I started having diarrhea on Sunday evening and took some Immodium AD.
Monday morning I began passing mucus instead of stool.  I also began having super foul-smelling gas.  Still having cramps but started being able to eat a little bit (with cramping after eating).  I then had another normal bowel movement.
Tuesday morning I had a tan colored stool that was formed.  Also continued having gas and lots of belching.  Cramps also continued.
I also breastfeed a 3 month old.  I know I need to eat because my milk production has decreased; but every time I eat, it's followed by foul-gas, belching, and cramps.
I was around someone this past week who was vomiting and had diarrhea and am wondering if I just have a simple sickness or if it could be something more.  At any rate, I need to figure out something as my little one needs me to be healthy so that my milk will increase again.
25 y.o. female, no drugs, no meds, no alcohol, non-smoking.

[keljessam]

I was searching for my symptoms to see if any bugs are out there and I came upon your note. I began having stomach cramping on Wednesday around 7:00 pm. I had eaten left over pizza and a smoothie from the mall. The cramps woke me throughout the night and continued into the morning. The only other symptom I had was non-stop belching and very foul gas. I had only one bowel movement on Thursday; it was not normal, rather I was constipated. I drank juice and water and had oatmeal on Thursday. The cramps came on again strong this a.m. and I asked my husband to make me coffee, thinking that might move things. It did. It moved everything out of me and I'm hoping I had food poisoning and its on its way out of me. I think we both have the flu or food poisoning.