Gorbybelle,
Are you taking a probiotics like Florastor with your meds?
I haven't been on doxy, so don't know how it is, but I've been on other stuff that is known to be hard on the digestive system.
Florastor is a brand of Saccaromyces boulardii (S. boulardii) that my LLMD specifically recommends and it replenishes the good bacteria your gut needs to keep from getting C. difficile Hope75 mentions. That is very very nasty and can be life threatening in severe cases, so worth avoiding.
Your doctor sounds nice -- I'm glad! Take care.
Oh my, I hope you start to feel better. I had one course of doxy and I felt terrible after only a few days. It was that weak dosage that the CDC recommends. My primary doc prescribed after my positive ELISA. You said your digestive system is upset. You don't have C-Diff infection do you? (diarrhea - it's quite terrible) I would definitely get that taken care of if so, and quickly.
It is nice to speak to someone who knows your pain. I feel your pain too, so take care and feel better soon!