You don't "have" to act happy in front of your parents. They might prefer seeing you happy, but that's because they care. I'm sure deep down they'd rather you were actually genuinely happy. You should consider talking to them.
Also, try to find things to do that you really enjoy doing for whenever you feel lonely, it might help you feel a little better. Things honestly can get a lot better, you're 11 and you have your entire future ahead of you, try to keep positive.
I'm sorry you feel lonely, you're a really nice person and you deserve to have people who appreciate and care about you. It's good that you posted here, don't be afraid to reach out for support whenever you need it. If you ever need someone to talk to feel free to
PM anytime too.
