I'm sorry you're having a hard time right now!
First of all, hormonal fluctuations that come with your period can mess with your digestion. You could have picked up something as simple as a bug - diarrhea is contagious. Anxiety can also cause diarrhea. Stress always hits me right in my gut.
Treatment for diarrhea can include Immodium AD, and a BRAT diet: bananas, rice, applesauce, and toast. And drink water to avoid getting dehydrated! It's good you're trying to get some protein in. Also, a daily probiotic might be of some benefit, too. You can buy those over the counter at any grocery/drug store.
If the symptoms keep bothering you, follow up with your doctor. But it sounds like you have a lot going on in your body right now, so just try to relax, treat your body kindly, rest, do what you need to do manage your anxiety. Hang in there!
I've also been having moderate to severe panic attacks all week