Since you'd be here for summer, I assume you're an exchange student.
You have nothing to worry about. Exchange students have all the fun. You get introduced to other exchange students like yourself. You'll make more friends than you can imagine from orientation activities and stuff that'll be organised for you. The exchange kids I see around my school (NUS) always know someone along the hallway, so I reckon it's not that bad.
Singapore's a melting pot of nationalities. You'll get to meet loads of people. You won't be lonely, that's for sure.
It's safe and clean, so that's nothing to worry about. All you have to worry about is finding the cheapest bar/club to have fun in. That's what all students do anyway.

And most of them exchange kids I know, go to Dbl O. Anyway, if you need help, just smile and ask. Locals are more than happy to guide you.