Is it normal to think i'm not understood

yeah its normal because no one has the exact same life life that you have.

No one is ever understood.

No one is ever completely "known" by someone else.

It's a painful truth, I know, but it's what makes being an individual and an original soul so unique and special.

Yeah. I feel like noon understands me sometimes, but the key is to find someone who is almost exactly like you, and be there friend. It will help a lot, because they will understand kore Than most.
On the other side, you could just try getting out and meeting people, and meet someone who is the exact opposite. They may not understand you as well, but they can show you the other side of things, if you can tolerate being around them.

And no one ever will. Seriously, it would be impossible. I know you feel lost though. Try finding friends who are interested in some similar things and try to work on being more positive and communicating better. Hope it helps!!