number one what sort of thing would you be going to the hospital for? unless it is clearly mental health realated they are unlikely to check for injuries question you about it. If you are going in for something completely different they may try to talk about if they see but (i think this is right) it is completely within your rights to refuse to answer.
number 2 if you go to get help at docs they see it as a positive step so are more supportive than judgemental most of the time.
number 3 taking kids away is a last resort. social workers will always try their best to keep families together.
good luck, maybe look at samaritans if your in the uk:
http://www.samaritans.org/ they good at info and helping things calm.
also people on the mental health board here might be able to give you spefic details on your rights under mental health act what happens to kids im only 17 so im not an expert just thought you desrved a reply j x