OP I am a GP and have bipolar 1 disorder and I would really recommend seeing a private psychiatrist through the Priory or similar on a semi regular basis (if you are self paying do look for one who is potentially willing to see you on an ad hoc basis after the first assessment rather than being locked in to seeing someone every week or every fortnight if that’s going to be less affordable for you).
I self-pay to see a private psychiatrist and the difference between that and the local NHS mental health services are like night and day. What a lot of people don’t understand about modern NHS outpatient mental health services is that often you’ll end up seeing a social worker or mental health nurse or something rather than a doctor training in psychiatry let alone a consultant psychiatrist. So they don’t actually have the training or qualifications to eg make a diagnosis or alter medication etc.
I think it will be money very well spent OP, it’s transformed my life ever since I made the switch. But sometimes it can take a bit of trial and error to find the right person. Read up on their background, their qualifications, their specialist subjects, and find someone who you think sounds like they will be able to help you. I have personally found it much better to see older psychiatrists who are more experienced but the risk of that is that they retire and then you have to find someone all over again.
I will say that from what you’ve written so far it doesn’t really sound suspicious of bipolar disorder, everyone seems to think they have bipolar these days but often what you’re experiencing is chronic depression with episodes of being less depressed or “normal” in between, rather than having true “high” or “up” periods where you eg don’t sleep because you feel it unnecessary, think you’re are a goddess or whatever and start sleeping around or spending money you don’t have or doing other things that are super out of character.
I would also suggest that you ask to speak to the practice manager at your local GP surgery and let them know that you really want to find a way of seeing the same GP each time or at least most of the time, if there is a certain GP you feel deals better with mental health issues then ask for them, or if you don’t know ask the receptionists who they would recommend booking in with for mental health issues; they will know who is good at dealing with that side of GP and who is not! Sometimes our patients complain to me that they don’t see the same person each time but a lot of the time it’s as simple as they’re not asking to see the same person each time and so reception is automatically just giving them the next available GP appt. I tell my patients to just ask for me when they call but they have to bear in mind that as I work part time they won’t be able to get an appt on certain days of the week when I’m not at work, or if they call up needing a same day emergency appt that also might not be with me if I’m not the emergency doctor that day.