Well, any and every other doctor you would see WILL be aware of your complete physical and mental health issues. Your medical files go with you wherever you go and part of a physicians [i]first[i] responsibilities is to familiarize themselves with it.

There are physical health issues that could cause this - like hyperparathyroidism, and thyroid issues like Hashimoto syndrome, Diabetes Insipidus, and I could go on and on. I only know about these off hand as I've recently gone through testing for them. Your mental health need not have anything to do with this; but, in some cases, medication (lithium) could have triggered these issues - they don't go away.

Again, go to your GP and inform them of your concerns. And, yes get that second opion if you need to. What should happen is that the doctor orders a requisition for a pretty comprehensive set of blood tests.