I'm sorry for what you're going through and, unfortunately, I can definitely relate!!!
I, too, have a mysterious painful medical condition. It started in my first pregnancy in 2007 and I've been in constant, every second of every minute of every day, pain too. Yesterday, in fact, I saw the 20th doctor that I've seen in these 5 years hoping to find some relief.
Ironically, I, too, have interstitial cystitis, in addition to the (seemingly unrelated) first medical condition, which is neuropathy.
Interestingly, both of mine are exacerbated by things I ingest - foods, drinks, medications, so it's possible that they are related.
I seem to have many doctors appointments a month and am always trying some new diet regimen to see if I can eliminate problem foods.
Sadly, the process has tainted me and I will say that I respect a lot of doctors less than I used to. I have had several do what yours did which is the attitude of "I have no clue what you have. But since you're here and I want to bill your insurance and make money, let's see if I can find something else to treat you for." I drop those doctors like hot potatoes. I find it insulting to my intelligence and to me as a person to be treated like that. I'm here for a specific problem and that's the one I want help with. Yes, I do have other ailments, but my neuropathy runs my life and makes me miserable, a pimple, for example, is so low on the priority list that I'm actually happy to have it just to take my mind off of the main pain.
I have stopped wasting time on doctors who are like this. I think a second chance is fine, but you've already given him that. You do not owe it to him. You owe yourself to find someone else. It takes time and effort to go to these appointments. We live 20 miles from our capital city and I find that the doctors and hospitals are better there, so now, appointments can take up half the day because I have to drop my kids off at childcare, spend money on childcare, drive to the capital city, wait for the Dr, etc. Anyone who doesn't respect me or seem to have a good plan of action, I discontinue seeing.
So, in your shoes, I would find another primary care doctor. Check out vitals_com, healthgrades_com, ratemds_com and yelp_com (I put in underscores instead of a period so a filter doesn't think they're spam or malicious) to see if people have good things to say about a doctor or not.
What has helped me tremendously is like a PP suggested - lists and charts. I have spreadsheets. I list all the doctors that I've seen before the one I'm talking to at that moment and their specialities. I list all the symptoms I have. I list all the things I've tried and their results (usually, more pain). I list the foods that I can tolerate (to demonstrate that living on honey and beef isn't very healthy and I would like to be able to eat things that would be better for my longterm health). I just list the facts and focus on those. I have not had to cry or use emotion. I just really try to describe my pain "It's like someone is driving nails into me at all times" or "the feeling you have when your foot falls asleep and is moved again - yeah, I feel that 24/7 but it gets even worse after I eat."
But I do think you should just find a new doctor. I can understand this one being distracted or having an off day. But I am upset on your behalf that he skirted around the main reason you were there. I find that disrespectful of him, no matter what had happened to him recently.
I have had a few say to me "this must cause depression" and I say "It sure does. That's why I need to fix my health issue." Personally, I don't have time for even the appointments I'm going to. I go online to medhelp_org and post there when I need to vent about how much my life is limited by this. But, mainly, I keep my spirits up by trying to self-diagnose and see what I can do to change my situation.