Oh, Devon! I'm sorry that you're having such a crappy week. When it rains, it pours! For sure. However, I agree with Kelly that being pro-active about the whole situation is a plus. Contacting your customers as soon as you realized that there's a problem is a good thing (even though nobody wants to have to send those messages). I'm sure that, if you go above and beyond, your customers will be understanding and even appreciative. We all make mistakes!
I once sent three sets of bibs out and, not until the customer contacted me did I realize that I had sent one set in the wrong size! I profusely apologized and sent a replacement in the correct size the next day. Thankfully, the customer was very understanding and kind and had ordered well in advance of a baby shower event. She received the replacement set in time for the baby shower and was a happy customer.
I told her to keep the original set and, of course, didn't charge for shipping on the second item. I'm more happy to pay for my mistakes and have a satisfied customer who will likely refer business to me because, although I might have made a human error, I made up for it with customer service.
Chin up! Rest and relax as much as you can. I hope you feel better soon.