I was diagnosed with Shingles about 10 days ago and now for the past few days both my French bulldog and our Shorkie have become sick especially...

Oh no! I hope you feel better soon. The two are likely unrelated though. The diarrhea could be caused by a number of things, usually something they ate that they're not used to. If your area has had a lot of rain lately, it could be giardia, which is a parasite they can pick up from standing water. 

Both of their breeds are also prone to pancreatitis, which is usually caused by something they ate (people food, new treats, quick change in diet, etc.).

If they are not having any vomiting, and are still eating and drinking normally, you can try feeding them plain boiled chicken and plain white rice, as well as adding a little canned pumpkin- not pumpkin pie filling - (about a teaspoon twice a day) to help firm up their stool. If that doesn't help or if they continue to have diarrhea and/or start vomiting or losing their appetite, I would recommend taking them to their vet. The vet may recommend a pancreatitis test, fecal check, giardia test, and/or further bloodwork.

Hope this helps!

You are welcome