Yeah, mixing your real persona with your character in order to flirt is just asking for trouble. At best she'll just think OP is roleplaying like everyone else at the table; if he pushes it too far it goes into creep territory.

I get why it's tempting to hide behind a character to test the waters, but he's better off making his intentions clear out of game.

You did the right thing. Like with physical wounds you have to let mental health concerns out in the open air so they don't fester and get worse. Thoughts like this do happen to most people at one point or another, but if it's happening often enough for you to feel the need to tell someone, you should definitely take it seriously.

If you have the option, I very much recommend a therapist. Worst case scenario you stick it out for a bit before deciding it's not for you.