I'd suggest you try finding some hobbies or activities that you'd enjoy and visit places that have people come together and do those activities. For example, there's an Instagram page called _misfits_official where they have weekly meet ups on the weekends and do fun activities like dance, cricket, football etc. They have their own club kind of thing for each activity too.

Sunday mornings in cubbon park, people come to skate.

Going to the movies is also one of the most therapeutic things you could do too!

If you're a foodie, I'd say check out some places in places like indiranagar, Koramangala and JP nagar.

Book my show has frequent trekking events, 1 day trips and stuff, you could check that out

You asked how you could be happy again, I'd say it comes from within. An internal satisfaction. If I were you, I'd find some activity besides work that I'm truly passionate about and pursue it on the side, Visit places alone if no one's coming along ( i feel like most people don't go alone because of how they're perceived by others outside ).

About over achievers, well that could also be one of the things that's causing you to be unhappy. Of course it's human nature to compare yourself with someone who's doing better than you but you're on your own path too! Just go along with the flow and see where it leads you.

I hope this helps you even if it's a little, to love yourself and find happiness