((SM)) i loved what cantstopcrying suggested . can u do that?
but if that isn't an option how bout starting to network now to make new friends to fill that "hole" when you irl friend makes her trip? what are your interests? that's a start. join a group, any group, or do some volunteer work. sometimes the best things happen in the places we don't even expect it, but we need to open the door for that to happen. i always say, the hardest door for me to open is my own. i have agoraphobia a lot. so i have to take out the crowbar and wedge myself out the door!! the more often i practice this the less scary the outcome is. you can even "practice" on making new friends.
or just take a walk in your neighborhood. when you see people out maybe in their yard say hello and comment on whatever they're doing, like yardwork...see if you can get a conversation going. this has worked for me in the past.
as for not telling people about your depression i know that i am very, very careful who i divulge this info with. so many people (norms)just don't understand it or want to understand it. so i think that's ok if you don't feel comfortable talking about it much. it's not necessary for people to know. on the other hand, if you can develop a good friendship, one where you see good and caring qualities in the person, it's usually safe to share if a situation calls for it.
"chatty-cathy" (me) needs to quiet herself....i hope this helps in some small way, ((SM)).