so sorry to hear this. I have a lot of experience with younger teens and depression as my daughter was very unwell. I hope this practical advice will be useful, as I know how terrifying it all is.
Your DD is the most difficult age in terms of accessing the best mental health support so I hope she is not 18 for a while as you have to change to adult services where there is much less help. Ask them how long CAMHS will help her for. Very few trusts have places which look after teens until 21 eg. Tavistock in London, so do check.
I'm afraid often as parents, we need to fight quite hard to make sure our teens are getting the best care and advice and quickly from CAMHS who are underfunded and underresourced. .
Firstly under 18, it is unusual a to be put on anti depressant by a gp. As a teenager, She should have been referred to a CAMHS psychiatrist who would allocate meds if necessary and should have a talking therapy alongside any medication . Often, too, different types of medication are offered first which have lots of research done for young people. Try to read NICE guidelines on young people and how they should be treated for depression to arm yourself with CAMHS.
It sounds to me like they are treating her like an adult but she is legally CAMHS until she turns 18 in most areas. .
Make sure she has given you permission to deal with CAMHS on her behalf, as she is over 16 .ask your DD if you can go in for part of her assessment with the psychiatrist (she may not be well enough for this or want this which is fine) or if its difficult as your daughter will need most of the session, email the psychiatrist directly after the assessment (finding out the name of the lead psych to copy in) and ask the following.
Check with the CAMHS psychiatrist that her medication is being reviewed ( a lot of these medications have bad side effects going on and going off and should be fully monitored by camhs)and say that you wish to know more about why she is on that particular medication ,given she is a teenager . how are CAMHS going to monitor it ? Express concern that it was prescribed before seeing a camhs psychiatrist.
Ask that she have urgent regular talking therapy alongside medication as you know NICE guidelines suggest medication be used alongside a talking therapy for young people. Young Minds charity offer a callback service where you can speak to a camhs professional and this might be worth doing, so you are armed with what help she should be getting.
If she continues to be suicidal and a danger to herself, and CAMHS say she needs to go into hospital, look at the adolescent psychiatric hospitals used by CAMHS in your area, so you know which ones are nearer. The idea of an adolescent unit is frightening I know, but if she is a danger to herself and suicidally depressed, it it will keep her safe, and is a better option that what is available over 18.
For yourself go to your GP, explain it, ask for short term CBT and this should help you manage your emotions. As she is all over the place, outwardly if you can be calm and consistent it will help (very hard I know and I certainly wasnt calm with CAMHS).
Forget college for now, depression is an illness and it can take quite a while to find the right support and treatment for your DD and for everyone else to cope so keep that pressure off at least but when she feels stronger, she will be able to pick it up. (My DD is now at University and missed a lot of school and college). I really hope CAMHS is supportive to you and the family but you may have be tough to get the best help. I hope some of this is helpful.