Forged a Doctor's signature on an excuse for my professor.?

First of all suicide should not be an option. This is just a college cl. If she flunks you then you can always retake the cl. As far as the illegal aspects of the situation that depends on if your doctor or prof ever finds out and reports you to the police. Getting kicked out of school also depends on if the prof contacts the dean. These are all things that you cannot control right now. Relax and wait to hear from your professor. It will be hard to wait but perhaps in the meantime you will have learned a very important lesson. People make mistakes and mistakes can be fixed. Killing yourself should never be an option.