I Think I'm Bipolar

It's hard to explain. Obviously I'm not going to diagnose myself, I shall maybe see someone if it gets worse. However, I can have certain episodes where I completely shut off, I zone out of nearly all conversations I am in and I just end up feeling genuinely down. This can happen for a few days up to weeks.

Then I'm suddenly happy and motivated for a couple of day to a week. I'll do my work, tidy around the house. Maybe go outside with friends and actually speak more to people.

Then I have random episodes where I'm sad and snap at people or I can be happy and then easily irritated.

However I'm fully aware it can easily be confused with depression, that's what I thought it was. But it just doesn't seem right to me