I'm concerned that your doctor doesn't want to be honest with you. It sounds like you would feel more secure if you truly knew where you are with all this. Instead of trying to diagnose yourself, maybe it would help to see another doctor who will be more upfront with you. The meds they have you on are BP meds, but I think you need a solid answer so you can go on from here and try to start healing and learing how to handle this disorder.
I understand the rage-I think most of us deal with it, but there are ways to help control it. I took DBT classes and it did help.
And you should always take your meds as prescribed. If you get another doc, they may change your meds and it may help what you are going through now.
Very simply put, BP is an imbalance of the brain chemistry and from what I have read, you are born with it. There are different degrees and some people never know they have it. When the symptoms are severe, sometimes all it takes is a triggering event to bring it on. My trigger was being raped.
Please don't take what I say for gospel-I'm not a doc. But I am in my sixties and have dealt with this all my life. Rage is still a problem for me, but I've learned ways to handle it most of the time.
But do seriously consider getting another professional opinion. You can't know how to handle a problem until you know what the problem is.