Alright OP, I want to give you a little bit of background.
I used to be a loser. A real big one. Overweight, "friends", no real life, constantly the butt of people's jokes, an omega, etc.
I had to learn the hard way what I'm going to tell you right now. The reason you lost those "friends" is because they didn't respect you and they saw weakness in you.
People say that human interactions are complex but they really aren't. People will follow what the dominant personality establish and will reject and mock what is not the dominant personality. You make the mistake that most people make, and that is that logical analysis and talking will win over people. That is not how the game works.
In every interaction, there are multiple levels of communication, the biggest of which are
1.) the emotional connection/status of the individual
2.) the prevailing group theory
3.) The subtext of the conversation
4.) The context of the conversation
5.) Words being spoken
An example of this: Netflix and chill
5.) Netflix and chill
4.) He wants to hang out with me
3.) He wants to fuck me
2.) Will people think I am a slut, is the guy acceptable to sleep with?
1.) Am I horny, and is this guy acceptable?
watch this scene and pay attention:
youtube.com/watch?v=IXLFPLqqf5E
You, my friend, are operating only on the words being spoken. I can guarantee you that you were seen by the group as being weak, an easy pushover, or of low status, given how they started to ditch you and stop talking to you. You had next to no influence in the group and they shunned you. If this was a dog's family, you would have been the runt of the litter.
The best thing you can do for yourself is to read up on how to communicate effectively and the reasons why. Being physically strong, emotionally centered, and a masculine personality are necessary not to be treated with disrespect. If you want to be listened to and not lose "friends" then I suggest you also read these books: