School is in but I am graduated, not around, and replacable...

So I graduated last school year which was amazing because now I can make some money and move on with my life. I wasnt very close to my graduating class of '07. I grew apart from my old friends in my last year and grew closer to my best friend ean and his other friends in the grade below me. 
Now schools back in and all my friends are now in the same spot I was last year, but I'm not there anymore. I'm employed and an active cog in the matrix and uh... 
Well i didn't think there would be NEW people entering the school that I don't get to meet, I don't know why that never crossed my mind. I've never even met them before and I feel defensive and jealous because well... what if you replace me? 
I'm not around to take up my space I've left a space, and other people can fill it now. I'm missing out on six hours of stories and socialization which like DUH. but DAMN It kind of hurts more than I thought it would. 

I feel like because I'm not around, all my friends are only going to grow closer while I grow further apart. I'm afraid my friends are going to forget me and replace me, not on purpose of course... but just by the natural order of things. I'm not apart of their natural order anymore and that causes like a long list of negative emotions I DONT want to deal with because I'm TRYING to get off of escotalipram without spiralling back into depression. 

I feel like I have to isolate myself from them and cut them off before they accidentally cut me off. A part of me that I don't particularly like wants to find new friends and do to my friends what I fear will happen to me. I don't know why I want to make them feel as replacable as I feel, but all those feelings make me feel like a fucking shitty friend. Who thinks of something like that??? 

regardless of any of this, I don't have any friends that work full time and are at the same place in life that I am. I want to find people in my life that are a little bit more relatable to the position I'm in so I don't feel the need to cling so desperately to the past. I feel like I should branch out so I have someone to fall back on if I do get replaced. But that whole train of thought makes me feel guilty for wanting to find friends in a more similar position to me that don't go to school anymore. I don't know man. 

But at the end of the day, I don't even know if all these thoughts are things I actually feel, or if It was just a shitty idea to quit my anti-depressants cold turkey without talking to my doctor. FFS, WTF. 

Thanks for reading if you read, sometimes a guy just wants to feel heard and you helped me feel heard