Just see the fact they're doing all the tests as a positive that hopefully you can get some answers and start towards feeling better :)
I mainly asked with you mentioning depression as most of the people I've come across are those with eating disorders, esp with laxative and diuretic abuse and making themself sick etc... so was trying to gauge if any of that was an underlying reason.
Dont scare yourself by looking up things too much on the net, so easy to get carried away and end up thinking all sorts.
It can be really hard if you're feeling crap. Ive found it veyr hard going lately as I've not been well and seems ot be one thing after another but you just have to pick yourself up and not let it drag you down.
Why not treat yourself to something you enjoy, see some friends and have a good natter, do some pampering, whatever you fancy.