why is it hard for me to deal with change?

[Jonluc Board]

Basically last year everyone I knew turned 18 and obviously so did I and ever since everyone I know has changed and become something they're not and it's breaking my heart. I keep looking back over my Facebook and twitter pages and reminisce about how good everything used to be and keep wishing everyday and every night that things would go back to the good old days as I call them.

I had a bad incident in 2010 and noticed people becoming different, back before everyone turned 18 I had everything, a good life, perfect girlfriend and a nice job, but ever since turning 18 life has become rubbish and I suffer from major depression and now it's at an all time high and I've started using alcohol and cigarettes to treat it as therapy/counselling doesn't work.

someone please help put my mind at ease.