Homesick at home

Is it possible to be at home and still feel homesick? I come from a big, close family, and right now, my sister's in Egypt for 3 weeks to visit extended family and has my niece with her, which is the natural thing for a mother to do, I know, but having gotten very very used to having this little angel next door to kiss and squeeze and love at least once a day is making me very antsy at the distance between us right now. It's almost enough (but not quite) to make me realise how much I miss my sister herself… To put it lightly, we're attached by the hip, and right now, despite the fact that I'm keeping myself good and busy to help the time pass, I can't help but notice that it's gonna be 3 weeks before I see them. That's right, they've been gone less than 3 days, and I'm already in withdrawal...
So what's happened as a result? I'm suddenly missing Montreal, where my next nearest sister lives, and had a good long conversation with her on the phone last night… I'll be going down to see her in 2 weeks (Yay!), which right now seems 2 weeks too far away (Boo!), and I might get a chance to see a close friend who's there right now too… Am I normal? Does everyone with a big family and lots of company get like this when they're surrounded by less people?