How to Determine if I Have a Gluten Intolerance or Red Meat Intolerance?

How do I tell if I got gluten-ed or if I have a food intolerance to red meat? I've never been a big fan of red meat, but sometimes I eat it. When it comes from places like Taco Bell, my stomach only hurts a little bit after I eat it (which until now I figured could be bc of gluten cross contamination). However, I decided to make some beef at home that I know is 100% gluten free for tacos, and it's made me SERIOUSLY sick. The other toppings I used have never made me sick before; this was my first time using unseasoned beef in tacos. Three times now, it's made me sick. (also I only ate two tacos each time, so I know it's not because I ate too much). I know the meat isn't expired because my dad ate it just fine and he usually is more sensitive than me to expired foods. If I was gluten-ed, where could the gluten have come from? I bought certified gluten free ingredients. If I have a red meat intolerance, how come Taco Bell tacos and seasoned beef don't make me as sick? Has anyone been in a similar situation before?