You need to tell your rheumy what the PCP gave you as far as meds go and your decision not to take the prednisone.There is a potential interaction between the Cellcept and the Z-pack.Perhaps call you prescribing dr to discuss or the rheumy or your pharmacist if you werent told at filling.
Did you test postive for the flu?If so you need to contact your rheumy and let him/her know this as it may cause him to change your treatment plan until you are flu free.
Please make sure that your drs are aware of what the other is giving you as there is a potential for great error if they prescribe medications while not knowing others that you are taking.
If you are having issues as far as trusting your rheumy or not feeling that they are spending time adequately with you appt or exam wise perhaps you would be well served in trying to find one that you are comfortable with.I had alot of PCP issues once I was diagnosed and on prednisone and started DMARD treatment.My PCP felt my illness was "outside his comfort zone" with the types of meds I was on regularly and I spent quite a long time finding one who wasnt freaked out.I cherish him and my whole team.
If you cant trust your dr in treating you and dont feel like he really pays attention perhaps bring it to his attention.If his manner doesnt change or you still dont like the care you are receiving then perhaps its time to find another dr.