I'm having a desperately hard time right now, and I was wondering if I could get your opinions?

I started going to therapy in August after I overdosed, but I only had 6 sessions and I finished 3 weeks ago to take a break and think things over i.e. whether therapy is right for me right now. I realised about a week later that I needed therapy, and I needed my therapist also, because she helped me with quite a bit, although I didn't really talk much in our sessions. I called her office about 1 1/2 weeks ago, and the receptionist passed me on to her line manager and she told me that I'd have to wait a few weeks because there were no free slots, an I was absolutely fine with that.

Recently, however, things have been getting worse. A few examples are:
-sleepless nights
-sleeping too much
-eating hardly anything - resulting in weight loss
-suicidal ideation
-self-harm
-difficulty getting up in the morning
-unable to concentrate in college
-not doing homework or revising for tests
This list could go on forever, but those are a few examples.

I really feel like I need to talk to my therapist so I can get a feel that she is still there for me, and i can get a glimpse of hope that things will get better. My worry is whether I would be 'told off' or refused contact with her because I'm not technically her client/patient, even though I was. So is it a good idea to contact her.

Just a note: I have my therapist's mobile number, yet I've never actually called it. I'm scared to call or email really, but I think I need to. If you think it would be okay for me to contact her, could you tell me how I would start off?
Also, I'm a 17 year old female.