Going Going Gone

Man if there's one thing i really don't like its having to say goodbye. When it comes to short term farewells, people I'm going to see in the next week or so i don't have problems with. (If that short time frame was an issue it would be very difficult to get threw a day!) The time frame of 3 weeks or more when someones going to be gone, i get sad. But the thing is it shouldn't make me sad especially when i know I'm going to see them again. Then what i do to overcome those feelings is put them out of my mind and almost forget about them because i know when i think about the person i will get sad again. I guess what this shows is that i really care for everybody that I'm in contact with, and that i have a heart. I'm not one to cry that often but the whole leaving thing really gets to me. Usually i deal with emotions with laughter, sometimes good sometimes bad. Somethings scary i laugh, something sad i laugh(not always the best emotion to have), i'm frustrated i usually laugh. So you'd think that with the whole leaving thing i would be able to laugh and it would be all good. Nope! Is this a fairly common thing, or is this just me? Is there something else that effects you like this?