Sounds like bipolar from what you describe. Sleep is a good indicator as never.more says. I sleep for 3 to four hours before waking up in the middle of the night can't go back to sleep until about 8 and get another 3 hours till 11. I can't get up before 11 am and if I do I feel groggy for the whole day.
I used to think I had bipolar 2 until some people I trusted gaslit me and sent me into a manic episode and psychotic breakdown that ended up ruining my life. Post that I got a diagnosis of bipolar type 1. The key trigger for bipolar disorder is stress. I have a theory that these distinctions like bipolar type 1 or bipolar type 2 or cyclothmia are just superficial taking into consideration past behaviour until that point.
I think that under an adequately high amount of stress, every person with bipolar disorder will be shown to be type 1. The illness is neuroprogressive meaning symptoms will only get worse with time.
During my depressive periods, I used to be in a general haze with brain fog and general incoherence, no energy to do anything - not even a bath. I take a bath generally every 2 weeks - that would be a good clue as well. I'd be reclusive, not going out or seeing people for days. I used to stay up all night with a bad porn addiction. Hypersexuality is another key indicator of bipolar disorder.
In the hypomanic phases I'd have really elevated mood, very talkative and sociable and articulate, cracking jokes non stop. If you can picture the molecules in a gas jostling against each other, that's how my brain would feel. It'd be like a pinball machine.
I've only had one manic episode and jeez I felt like I could change the world. Everything was on a grandiose scale with insane amounts of self belief. I literally felt I could do anything. Be a musician, get into politics to "fix" the world, write literature, become a stand up comedian. I got ideas faster than I could write them down.
In the hypomanic and manic phases I felt I had what one would call "forced speech". I think in psychological parlance it is called elevated motor function. Once I got going, it takes a bit of an effort to stop and also rapid speech where the words run into each other and hence the speech is not quite clear to the other party.
I've had very little periods of euthymia where one feels pretty close to normal. My euthymic periods feel like low key depression where it may not be that bad, but still lurking there. It's always a cycle between depression and hypomania, with depression being there like about 80% of the time.
So yeah...I think sleep, hypersexuality, mood swings, features of depression (low energy, reclusiveness, incoherence, brain fog..), of hypomania (elevated mood, gregariousness, intense energy, lack of need for sleep.. ) and mania ( grandiose thinking, risk taking behaviour, a feeling of almost going over the edge..) these would be the typical behaviour patterns that should give a good indication.
I accidentally found out after watching a show on Oprah that I may have bipolar disorder when I was very young like 19 or so, but wasn't sure. I told my parents but they always kept denying it. I had no idea how to go about getting diagnosis. Now I know that the way one gets it is by noting symptoms down and giving it to a psychologist/psychiatrist on a platter so that they can give you the diagnosis.
I used to have this really idealized notion of therapy and psychiatry where the dedicated psychiatrist would work like a detective, ask the right questions and piece the puzzle together and thus fix my life. Alas the real world doesn't work like that. So self diagnosis is often a good way to go about getting answers.
Bipolar by itself, I hear is manageable. The gold standard they say is lithium, but it is harsh on the kidneys. The general period is about 15 years before the kidneys reach the tipping point. With bipolar early intervention is key. Unfortunately for me I also have borderline personality disorder, ptsd, ocd and it got too late by the time things became clear leaving me with pretty much just one choice. I wish you better luck in your case.