Your PCP's made a good-faith effort to do everything he can think of --to rule out everything he can and to run any relevant tests. Now he suggests you see a psychiatrist. Why would you refuse to even consider that? No psychiatrist is going to make you take a medicine you don't want to take and it seems like you owe your PCP to at least follow his reasonable suggestion. He didn't say see a psychiatrist and take whatever drug he tries to prescribe you, did he?