Today is my 21st birthday and I just feel like things couldn't be any worse

I feel so lonely like nobody knows or understands me. On Saturday I went on a night out for my birthday with 15 of my friends, and as I was happy that they were there I just looked at them and thought "none of you even know the first thing about me".
My "ex" (who I used to speak to online) said that he might come out for my night out, so all night I waited for him to get in touch with me. When I finally did he told me he might come, and then later said he wasn't going to. The only person that mattered to me wasn't there for me and I just felt so horrible inside.
Then, to rub salt in the wounds last night he told me he was down because of "girl troubles" which obviously means he has been dating some other girl. That has been playing on my mind all day and night and upsetting me so much.
Today, my mum and dad gave me my birthday gift - a personalised car reg which they spent £500 on, I was not impressed. Not meaning to sound ungrateful, but I think people who drive round in them are flashy wannabees and absolute idiots, not to mention the things I could have spent £500 on my transition like for my laser work etc.
I told them how I felt and they wern't happy with my reaction, calling me ungrateful and arguing with me. I am thankful that they have got the gift, but its such a ridiculously expensive present which I don't like, money they know could have been spent so much more wisely. Just another thing that proves to me (after boxes and boxes of aftershave gift sets at Christmas) that my parents dont know me at all!
Hate to moan and hate feeling sorry for myself, but I just feel so upset today on a day which is supposed to be one of the best days of my life!