I have severe bipolar I, mixed episodes. it's not common enough that six people in your family have bipolar. people misuse the word to describe dramatic people, moody people in general, or people they don't like. it's why the condition is so stigmatized and I can't tell people I have it. Imagine how it feels to listen to friends and co-workers tell you a story about someone they know and at the end say 'that person is so bipolar, haha' and you are sitting there, thinking 'I have bipolar, is that how you would think if me if you knew?'.
To answer your question, mania is very noticeable to everyone around you and often gets people in trouble with the law or lands them in a hospital if they are not on meds. It can last two weeks. It has to last for at least a week to be called mania.
There are different types of bipolar. Some with highs first then depression. Or depression first then upswing in mood. Or mixed episodes like mine. Also there is rapid cycling bipolar where these swings happen more than four times in a year. The differences are very important for treatment plans.
This is a general look at the basic criteria of the condition, but their are many, many things that come with the condition, like struggles with perception of passing of time and keeping routines.
I haven't been diagnosed with this condiction. Only one therapist told me that I have depression after a test and some sessions. But there are times in which I'm excited and I feel lucky to be alive and I want to do many things, be productive. But some other times I want to end my life it's like another me. It's weird. When I'm in my happy (or excited) mood I regret thinking in ctb.
There is bipolar II which is depression with hypomania. It is missed by many doctors and therapists because when you feel good, especially after dealing with depression, you usually don't think to say to your doctor that you felt "too good". Hypomania has to last at least 4 days. A sure way to tell is to take antidepressants. If you have bipolar, antidepressant will trigger hypomania after some time.