For starters, you really should be closer to your parents. They raised you. They're not there simply to bail you out whenever your in trouble, they're their to care about you and you should care about them enough to tell them the truth about your life on daily basis. You don't have to lie, just omit certain truths.
As far as the hospital bill goes, talk to the hospital administrator about a payment plan you can arrange. Seeing as how you don't have a job, and I'm guessing no medical insurance, you can arrange a payment plan as low as $50 per month, sometimes lower depending on how well you present your case to the hospital. See about doing that first before resorting to telling your parents.
As for school, talk to the guidance counselor about methods of improving your grades. Present yourself in a sensible manner as someone truly struggling and try to negotiate a means to be removed from probation, or at least not be suspended next semester.
After seeing what you can do with the hospital and school, go ahead and go SEE your parents. Not phone call. Not email. Visit. Explain to them your stressed with your job and it affected your school work. Tell them you've felt emotionally distant from them but you don't want to be that sort of person and, hopefully, demonstrate that you've been able to handle yourself with school and the hospital. If those things don't pan out, you'll have to throw yourself at their mercy with the promise to do better.
Do your best and don't make anymore mistakes like that and you should be fine.