Referred to an endocrinologist, but they cannot see me until end of September, should I wait or what do I do?

Long story short, I've had issues, my doctor did a full blood workup, and thinks I might have a tumor on my pituitary based on certain highly elevated hormone levels that are indicative of such a tumor. 90% of the time the tumors are non-cancerous. Thus, it likely is not a life-or death situation.

She has referred me to en endocrinologist to have my head examined and to explore treatment options.

The endocrinologist office just called. They cannot see me until the end of September.

This seems a long wait to me, especially since I have severe reoccurring headaches and other issues that I would like to get resolved sooner rather than later (it has taken me two years and a dozen doctor visits to even get this far!)

So, should I call the doctor that referred me to the endocrinologist and ask for a different referral? Should I try to find my own doctor (not sure how that works with insurance)? Or should I just wait, assuming all others will be booked too?

Looking for opinions, advice, or personal experience on this matter.

Thanks.