It does sound like depression and it's good you're going to speak to a doctor. I have a similar story - used to be able to write stories and I was creative etc. But you should definitely see a doctor, I was put on medication and it helped a lot.

As for the sleep, do what rcat suggested, alter your evening routine. Sometimes it's what you do before you sleep that can trigger a bad night - not necessarily but it's a possibility. Try some light reading or something that doesn't work your brain to hard. Again, it's something to bring up to the doctor and they should have something to help. I was prescribed an antidepressant that I take on a night that makes me drowsy and helps me sleep, so definitely mention the sleep issues to the doctor.