Michiko,

I'd stop smiling and pretending everything was okay when it wasn't, that way you only hurt deeper - at least that was my experience. Number of comedians who do suicide because of having to pretend to be 'up' and 'cheerful' all the time seems quite big too.

With my parents, I sometimes had to cry out loud that I was in pain (literally, when something fell on my leg) and cry - basically do some 'drama' (it was genuine, but they just didn't get 'small hints' before) so they took notice. I don't have the diagnosis 'bpd' though, or your situation.

Basically if I understand it right, you don't want your parents to 'overreact' or fret too much, but you wish their cooperation and help. They do have to fret a bit if the situation demands it (ie if you've been feeling so bad) - they probably prefer an ALIVE daughter than an always-smiling one?

While you wait for therapy or mh hospital, you can do many things yourself too. Distracting yourself is good, but I'd limit computer usage - more than 5 hours a day can cause depression (?) There was a study in Japan! Why using a computer can cause depression | Daily Mail Online
A walk every day can help with depression, ideally in the sun. We know someone who cured her depression with walks.
Have you tried DIY CBT yet? I found The Feeling Good Handbook by Dr David Burns very helpful.
For some people, EFT (emofree.com) or TAT (tatlife.com) have been helpful too. I found them helpful for some things, TAT for the past etc.

Wishing you good luck!