Petesie, I feel this might be a case of your reputation preceding you.picked up a batshit crazy one who quickly turned into the trips stalker.
It seems Pattaya is right back into the low season doldrums & some of the girls would be quite desperate to land themself a "big fish". Even though you don't know her, she knows you.
Either that or you were just a wee bit too generous splashing the cash the night you met her. They have all met enough Cheap Charlies to know a prize when they see one.
You should be flattered but unfortunately this crazy girl has the potential to ruin your holiday. You may have to slip her a tip on the understanding she leaves you alone.
Good luck with it but don't make her lose face. They aren't beyond to resorting to other means. Be careful.