I have a friend that is diagnosed bipolar but they could never diagnose themselves. Part of bipolar cycles can be feelings that one may not be aware of or be aware of but think they are totally normal. A professional mental healthcare person is the best bet if you really want a professional diagnosis. I would not even venture a guess without consulting some kind of professional.
Of course there are people that learn to cope with their condition so it no longer disrupts their life, but that can be tricky especially if things get worse and that is not self apparent.. Lifestyle changes include mindfulness, exercise, meditation, diet and having good support people you can talk to that do not get tired or burnt out about talking about your condition.