There is no "normal" or right course of action. If you don't want to tell your mother yet, then I would give yourself permission to not do that. You don't have to work on/stress about telling right this minute.

A lot of one's stress and anxiety comes from worries and worrying is always about the future, which we can't know. You say it's going to be really bad at the cabin; how else can it be since you've decided that? You can't know for sure because you aren't there. But, we with anxiety don't like the unsureness more than anything else in the world so we "decide" how things are going to be and, that deciding usually locks us into more anxiety. You'll be anxious all the time at the cabin and that will reinforce how bad you feel about yourself and up it will spiral!

When you've gone to the cabin in the past, think of a time and activity there you liked? Is it nice and quiet/calm so you can read? Are there good places to walk or other kids your age that you use to play with? I like to read and so does my husband so we find bookstores or bring books and just hang out and read in neat places we find (seashores where you're allowed to drive your car on the beach (man-made spit of land) in the Gulf) and often I find a "workbook"/self help book and start a new project or journal. Maybe starting a journal of this particular anxiety experience and things you are trying to do to deal with it will help? Make this weekend at the cabin an "experiment"?

Think of things you enjoy that you find safe and relaxing (hot shower, clean sheets, camp fire (or fire in the fireplace in winter), sitting around and reading or talking to friends I know well and trust - would be mine) and figure out how to do some of those or be in those positions. You aren't going to have your "regular" walls and positions relative to the kitchen :-) or ipod docking procedures, etc. so think of yourself as being "free" of those problems this weekend. You could have a great time at the cabin. Climb a tree for me :-)