TL;DR: My boss is making me work Two full-time jobs while I work part-time hours. 

I work as an "office manager". It's a very small office, there's only a few employees, but we are BUSSSSYYYYYY! In order to be able to keep these employees hired, my boss applies for a lot of grants. This time, he applied for a grant that requires a new FULL-TIME employee to come on board, and the grant is used to pay the wages of said employee. He decided that I was going to be this person. Now on top of my clerical/office duties, I'm working as a person who helps small businesses grow their online presence. People in this position generally are new graduates, with great technical knowledge. I'M NOT A TECH SAVVY GAL, and I'm only working part-time! (horrible at handling stress) I'm completely out of my element, and I'm having multiple panic attacks daily. (Also heavily medicated for my anxiety). What do I do here? Should I talk to my boss about this? Am I being dramatic? I just need some advice