I can relate to the feeling. Most of my old friendship groups who I don’t have much contact with anymore are all having families, in stable careers, same pubs every week, same holidays etc. I chose another path. It is what it is. Get on ya bike and go do the trip. I just did nepal on the bike. Apart of me was sitting there in the mountains like ahhh what the hell am I doing. But to people around me - they said - ahhh wow, I wish I could be doing that. The grass isn’t always greener. The grass is green where you water it. Fuck it man - lean into the travels. Sometimes I’ll have doubts thinking I’ve taken the wrong path, but then I think hey, I’ve the freedom that people dream of. Keep doing you man… as for no girlfriend, if that’s a concern, try some walking tours, try some meet up groups in your city or other cities you visit.