Sounds like Bipolar-II, I do not know what a "mixed episode", even though I thought I did, but former pdoc said I didn't fit the criteria, and may have just been getting use to the meds, which was all new to me. I personally would only go with the DX the pdoc feels is it.
Until I saw a pdoc, my gp would just keep writing scriptsd for AD's claiming I was depressed,refusing to address physical problems.
I was later DXed by a Psychiatrist who after an evaluation (GP's aren't qualified to do, though they think so) concluded I was Bipolar-II(mild) and ADD mild.
I take 200mgs of Lamictal daily and Concerta, 36mgs in AM
Other meds to us ONLY if needed, Ativan and/or Klonapin, I really do ONLY use when I really need them, so I do not abuse them.

Just my 2 cents.
I can count the times I may have been slightly hypomanic, in my entire life (I'm 50) on one hand.
and this was always at the times I was taking diet pills (amphetamines) other than those times I was considered "clinically" depressed, and wasn't DXed with Bipolar till 2000, and I was on Phenterimine at that time, so truth be known, I may not be Bipolar, but still more prone to depression.
Whenever I try to drop down 50mgs from Lamictal, with pdoc's supervision, I'm good for a few months and then depression begins, no hypomania at all, I wish there was, at least a smidgen of it.
Hope all works out for you, take care now.