Prolactinoma- on meds and still increased prolactin

i am a 33 year old female,i have a prolactinoma and have been on bromocriptine. for the month of august i was on 20mg, when i got my prolactin levels tested they had jumped 11.1 when all other months the prolactin levels have decreased approx 15-20 ng/ml and my dosage has been less, 5mg-15mg where as my doctor has increased the dosage every month stating my prolactin levels have not decreased to her satisfaction. i am well aware that pregnancy will increase my prolactin levels even on meds but i am 100 percent sure i am not pregnant. right now my doc did not renew my script and has refered me to an endo however it will be december before i see him and i dont know if i should wait that long! if you could please give some ideas as to what the increase in prolactin could mean? thank you