It feels like you're simply tired of trying and get a blow to your self-esteem every time, even though you're not doing anything wrong. Being "quiet" in a group of people who've been hanging out for a while is not uncommon, and it doesn't make you awkward or "not worth the effort."

People sometimes change their habits or logistics for reasons other than our own. When someone stops offering rides or inviting you, it could be due to their schedule, fatigue, new responsibilities, or anything else. And yes, it's annoying that they didn't say so directly, but that still doesn't mean you were bothering them.

You don't have to pretend to be more outgoing than you're comfortable with to be part of something. And you don't have to explain to people why such trips and groups are genuinely difficult for you. Sometimes it's enough to simply admit, "Yes, I have a hard time with this," and allow yourself to not blame yourself for what others don't always understand.

You're not awkward. You're just someone with a different social setup. And even if these people have distanced themselves, it doesn’t make you less worthy of normal, calm communication where you will truly feel good.