Finding Friends and Coping with Constant Loneliness

If anyone has experienced a similar problem around my sort of age (16 - 24, I'm 18) please could I ask for some help or assistance?

For months (since February/March) I've finally gotten myself out of the house, absent myself from the screen, and attempt to get a lot of stuff done giving myself positive experiences and merit for myself (Gym 3 - 5 days a week has been my greatest). But I've started to realise a problem I've had for a long time right in front of myself, I have very few people I see outside of school (I go to an autistic specialist school) and have gone through most of my teen years without a peer group and now I don't feel as though I have ANYTHING to do at weekends or most days during my time off school/work,  it's negatively impacted both my confidence in myself and my future and my constant sanity from day to day and week to week. Going out and doing things (or having enjoyment from them) requires interaction with peers or person(s) with similar interests and genuinely having mutually positive relations.

This wasn't so much an issue for me last year, partly I didn't feel so isolated because I had video games, Paint.net, Cartography, Art,  and I still felt as though I would be able to reunite with distant friends who I still have contact with through Facebook, Instagram, Quora, Minds.com, etc.  But each time I've tried to contact anyone and asked to meet up; I've either received no further response from "Yo, How ya doing, Hey, Hi, What's Up", been declined with "I'm Busy" "I can't do this weekend, sorry" "I've got no time or interest today maybe another time" or not been able to meet up when we'd planned month or two weeks ago. I was even meant to meet up with two people from school to go to Greenwich and Thorpe Park both had to be cancelled because they were busy or unable to meet up.   The other problem is that I don't even feel I have family anymore, My Dad says he wants to help (and I trust and believe him, he's doing what he can since he's gone through similar phases to me) but doesn't often use his time to book or make arrangements to do things at weekends and has become increasingly lazy recently. Whereas My Mum has no genuine interest in sorting out my depression instead replying "You're entitled, you should be grateful of all the good things I give and do for you", "I'm depressed, we're depressed it's not all about you", "But you wouldn't be able to cope, or what if it doesn't work out".  Yet for years she's been holding me back from non-autistic-specialist  events, clubs, etc. and constantly treating me as though I'm a child or lower functioning autistic person "because I'm autistic" not even giving me a path for the same opportunities most people my age would likely have (again "because I'm autistic"). Like when she cancelled my NCS (once in a lifetime opportunity now gone) for similar reasons to the above.

Lastly, we lately traveled to Lucca (Tuscany, Italy) for a week (Jul 30th - August 6th) and although I enjoyed it, I felt really left out since Mum (I went with my Stepfather, Mother, Sister and Sister's friend) wanted to stay in The Villa (by the pool or in the kitchen or vinyard nearby) whilst I asked to go to see historic, cultural and natural landmarks as well as enjoy the local cities, towns, mountains, things to do, etc. Though we did go out a couple of times (mainly in the evenings to grab food out or take a quick view of our surroundings). I had two major arguments with Mum, one was when I felt she was treating me like a ten year old child in Pisa so I made myself appear big and aggressive to show her I was not one in response, and she accused me of being 'physically aggressive' when the only time I touched her was when I patted her shoulder twice in reassurance, we had to leave after 25 minutes. The other back at The Villa, when I tried to talk calmly with her about why I was feeling anxious and depressed she threwback "who are you to constantly blame me for everything bad in your life" and "be grateful, I give you (x), (x), (x), (x), (.....)" and "I've given you enough freedom so what do you possibly want more of?" so we argued instead, I was worried sick I'd made her or my stepfather uncomfortable to travel with me in the foreseeable future (though I will soon hopefully have my own job and will be able to book my own trips. What's the point or enjoyment involved in doing it completely solo? I really am grateful for all the good I've had, but all I would like is relations/friendships with leads to advance and create opportunities and things for myself to do and increase my pursuit of happiness        .