Nasat, you're fine, you're normal. You've realized something, possible actions, and the one i think it is you've decided on--dealing with it on your own and remaining open to your sister--seems like the right one.
If you grated on her at the end of your trip, that's normal with visiting people, too. Send a thank you card, or gift, or whatever, to her to let her know you appreciate her letting you visit and being good company. Them don't worry about it as long as things stay good between you.
As for, you, yes! Look into expanding your own life and circle.
You know, not everyone goes out with a bunch of friends all the time, or even occasionally. It's possible to have a few really good friends, whom you see only a few times a year, if that. Then there's the, week, more acquaintances that you might get pizza with or watch tv with. And creative people are often somewhat loners.
Don't feel that you have to live up to what you think are the expectations of others. What works for them may not work for you, and vice-versa.