Your therapist would know better than any of us, as they have seen you multiple times and I assume in multiple moods. I don't believe a single bout of hypomania without it having a negative effect on your life is enough to diagnose as BPII. There's a list of hypomanic symptoms as spelled out by the DSM, and you need to meet a threshold number of those symptoms to actually be diagnosed.

If you're concerned, I'd consult a psychiatrist rather than a therapist. They'll get a history, evaluate your present mood, and should be able to make a determination in no more than a couple visits at most. Best of luck on the journey. Regardless the answer, you're welcome to post here and we'll answer as best we can.