I just wanted to give you some (((((HUGS))))) Juliet.
I know that it really won't make any difference right now to tell you what you already know....the thing is your realizing it is a good thing because you have identified what you need to do in order to make the best of all of this. Drinking and using drugs is only going to keep you from getting better and add another thing to deal with.
You need to think of YOU and if that means cancelling plans with Gram so be it. There is nothing wrong with focusing on what you need to do to get past this mixed state.
When do you start the Seroquel??? Hopefully that will make you feel better about things...my daughter is on it and it works pretty quickly and helps alot with mixed states particularly with the depressive side of things. So hang in there and hopefully it will help.
You are not useless....nobody is. You are just feeling that way until the meds kick in. Please know that things will get better.....today is only temporary, tomorrow is a day closer to things turning around for you.
((((HUGS)))) ~ Goody