Lise,
It sounds as though you have a good idea of just how far you can push yourself right now. Your times are good, you are out there runnning do not be too hard on yourdelf. I do not have PVC, so I do not know what it is like. I do however think you have the right idea on turing the HRM off. I personally cannot stand the beeping, but if yours makes you nervous or worried it is probably best to leave it off, with the exception of periodic checks. Keep running and best of luck next weekend.