You don't have to be positive. Just be you, however you are at the moment
I'm so glad you wrote and you didn't disappoint. Are you disappointed, I wonder.

I think your appointment sounds like it was pretty anxiety-provoking. That's very understandable. First meetings, new people, the whole unknown aspect of it, is very hard. Being open is hard, talking is hard. It will get better.

The therapist and receptionist laughing I'm sure had nothing to do with you. They just wouldn't be so cruel. But it's a good thing to talk about when you see her again. All these things, all of our perceptions are important.

Can you contact the doctor who prescribed your Adderall, to see if they can help? Maybe find a way to buy them, or another medication that is cheaper that they could prescribe.
Especially contact them about the lithium, because that is a med that shouldn't be stopped suddenly. See if there is help for you that you don't know about, but they do.

I think it is positive that you went to the appointment. That's hard to do, but you did it.
What you are dealing with, with the medication is also very frustrating and very hard. I applaud you for keeping on keeping on!