Get a Grip

I really need to get a grip at the moment.
Outwardly things are going really well for me right now and yet I feel like I've got a huge black cloud over me. I am trying my hardest to be positive but I just feel bloody miserable. I can't shift it and its wearing me out. I know it's all part of my mood cycle. I've been really up lately and what goes up always has to come down, especially in my world. I know if I'm careful I'll work my way through it but I'm scared. I'm scared it'll take over and then I won't be able to do a thing about it. That's the trouble with depression. Everyone gets down and everyone reacts when something happens in their life. It's when there's no reason to be down that its so hard. It makes me feel like I'm being selfish . I am managing to keep a smile on my face in public but the rest of the time I just want to cry. Take yesterday, it was the perfect day. The weather was lovely and I spent the day with my Mum and Dad.We sat in the garden , had dinner and chatted. See...perfect, so why did I cry all the way home? I don't know what I want and I don't know what will make it better. I know all the things I'm supposed to be doing. On paper it's easy...eat properly, do some exercise, talk to friends, blah blah blah. Well it's not that simple. If it was then we'd all be happy and psychiatrists would be out of a job. Don't get me wrong , it helps to try and help yourself. I do try and take some responsibility for my health. It's just not that easy. I hate myself for being like this. I don't want to feel like this. Someone asked me what it feels like to be depressed. It's hard to describe. I expect everyone is different. I'd say it feels like shit. It feels like there is no hope, it feels like life is a horrible chore to be endured. I've never been very good with other people who have depression. I always think they should be able to sort it out , which does make me feel  bad. I should have more understanding . It's easy to sympathise when you can see what the problem is but not when someone is being so negative for no real reason. All I can do now is hope I can get through it without doing any damage. 
Since I started writing this it's got worse. I can't stop crying and I feel sick all the time. I don't know how much longer I can go without anyone noticing. Maybe it's to do with the fact that I changed my medication. I need to speak to someone and soon. If I get really ill again then everything I've worked so hard to achieve over the last couple of years will be a complete waste. Sometimes it's so hard. All I want is a bit of normality. Is that really too much to ask? I really do hate myself for being so pathetic.