Hi!

It sounds like you are a fellow over-thinker.

For the first example, I think the short answer is that people don't like confrontation. They might think it's rude to tell you what they want, so they just drop hints. I think the best thing you can do is to tell them how you feel. Something like "Hey, if you ever want me to leave or think I'm overstaying my welcome, just let me know. I don't do well with hints, so it would be awesome if you could be more direct. I understand people need their space and time, and I won't be hurt if you're honest with me about it.

For the second, just like struggle with overthinking, others could be struggling with things of their own. Some people get social anxiety and end up deciding that maybe gaming is not what they want to be doing. Sometimes people are forgetful and realize they need to eat or do homework or chores. Again, if it's a recurring thing and the person is someone you care about, it would be good to just tell them how you feel. Let them know that it's okay if they don't want to game or that it would be helpful for them to tell you if they're not going to make it. Either way, I think you should focus on enjoying gaming regardless. Have a game that you love playing on your own that you can turn to. That way you don't have to depend on someone else to have a good time.

As far as ASD goes, try not to give labels too much weight or self-diagnose. Also, it's not your schools duty to test you for that. Talk to your mom and see if you have a therapist within your healthcare provider that you can talk to :)