How long have you been on two pills a day? I relapsed when I cut down to one pill a day, but that does not necessarily mean you are having a relapse. The longer I was on vanco, the more problems I got with the stools. I would check with the doctor about going on 4 pills a day. That is a lot. Usually they put you back up one dose, which you already did. I did pretty well on 3 pills a day. I took one with each meal and none before bed. Some doctors test you while you are on meds. My Id had me test before I cut the dosage, but not everyone tests positive while on meds. But, supposedly the toxin would still show up, as the medication does not kill toxin, only the bacteria producing it. I never tested positive while on meds though, but others have.
Vanco also kills good bacteria along with the c diff, so you may be noticing changes in your bms because of that. I would definitely ask the doctor about your dosage. Also, are you on 250mg or 125mg pills?