I Have Had Valley Fever For Eight Years And Am

I have had valley fever for eight years and am still not dormant. My immune system is very weak in general now and I currently have a cold/virus, plus need a root canal (scheduled for Monday). I was prescribed a two week dose of penicillin by my dentist because of the tooth pain and am concerned about taking it because I have always been told that antibiotics feed the valley fever. Is this true? I don't think my immune system can handle another ping to it so what do you recommend? Take the antibiotic or not? The root canal is in two days so that will rid the tooth problem versus being on an antiobiotic for 14 days.
Thanks in advance.