Up and down

So today has been rather up and down. I slept most of the day again, until about half 2. The afternoon was fairly normal - felt quite down, moped around on the internet. Didn't have the energy to shower or get dressed or anything. Fairly typical. Then I watched So You Think You Can Dance, which was really good, and started making me feel all inspired like I did after watching Every Little Step the other day. Then later this evening I got really very hyper. My dad kept telling me to calm down. I was bouncing and jumping around the lounge giggling and talking very fast, and telling my parents all about various dance related things, and planning to go to London tomorrow, and talking about going to New York and all sorts of things like that. Then I was back to talking about dance classes, and explaining (rather fast) about how the dance exams work, and how I need to take X modern class etc, and my dad said to me 'Don't you think you're a bit old for all this?' (ie dance stuff, and wanting to be good at it), and I burst into tears and ran up to my bedroom. It sounds a ridiculously childish things to do, but it really hurt me, because he was basically voicing what I am always concerned (and indeed posted) about. That I am 23. I am too old to be still hoping for a performing career. Which to me then means that my life has no point and I may as well kill myself (simplistic, yes). So the hyper mood has completely disappeared - I spent a while laying on my bed crying, and wanting to hurt myself, and now I just feel like shit and want to self harm. I hate the way my mood can change so quickly. I can go from really hyper and excitable, to having strong suicidal thoughts in a flash, and I hate it.