I forged a signature thinking all would end up fine...all is not finely

So I'm doing an internship this semester that doesn't transfer college credit. I talked to an advisor and she gave me permission to take a really easy internship class through my school that would keep me enrolled and give me a P/F grade. The papers in the beginning of the semester I had to have signed my my internship supervisor by September 3, which is mandatory to pass the class. Since I wouldn't meet my supervisor until the 21st, I decided the forge his signature to get the papers in on time, figuring interns do this sort of thing all the time and that by the time mid-semester check in came along he'd have signed it. Turns out he cant sign it because it is too much of a liability to the company, though I've met others doing something similar and they had their paperwork signed.

So next week they have to talk on the phone to talk about my progress and I didn't sign one paper which my university prof said is an issue and she needs to talk about it with him. If they find out in their conversation that I forged the other two papers I'll definitely be removed from my internship and if I don't have an internship I'll fail the class. If I drop the class now to avoid all risk, I'll be 100% financially liable for the class and have to receive a W, which would be better but still might be overkill to the issue.

I'm wondering if anyone has a solution, or unbiased opinion please?? In hindsight obviously it would have clearly been easier to just have the inconvenience and bad grade of having no signature at all, but at the time I was trying to find the best solution to my problem and I did not think it would come to this. I really am not a bad person I was just trying to keep my internship class flowing smoothly and thought all would go well I never imagined it would get this felonious and now I'm extremely worried for my academic future..... please help me think of a way to solve this.

UPDATE:

Thank you all for your immediate responses and great help. I REALLY have learned a lesson and to be honest I am just going to take the W and quit my internship. This will not happen ever again, it was a terrible, terrible mistake. Thank you for your help.

Moral of the story: only sign your name always