Friend has been acting strangely?

You have a "disease" which I call and suffer from and that is "soft heart syndrome". You do have the right to pick and chose your friends, and you do have the right to not have friends who drag you down, or try to make you feel guilty. A pessimist person tend to be that way because if something bad happens, they aren't surprised, but if something good happens, then wow, that's great. An optimist is a person that if something bad happens, they weren't expecting it and then it is devistating to them. Apparantly, you seem to be the only friend she has, but you are just going to have to be honest with her and tell her you are in a time of your life where you are making some significant changes and because of your mental health you need to stay away from people that drag you down. Tell her you aren't trying to hurt her feelings, but to please give you space and time to think. The worse thing you can do to her is lie. Since she is a pessimist, this should not come to any suprise to her. She has that feeling anyway. Let her know iin no uncertain terms, that it's you, not her. It doesn't matter if she's not attractive. There are some beautiful people in the world, but have the personality of a dead fish, you following me? There are also some ugly personalities which cause people to become ugly, so looks aren't the main issue. Your happiness is what's is important and if this girl isn't making you happy, your best bet is to let her go. She'll find someone like herself to be friends with. Hope this helps. Good Luck and hopes this helps.