Last night i bent down and i couldn’t get back

Patient: Last night i bent down and i couldn’t get back up. I haven’t been able to straighten my knee since and i can barely walk. I’m only 19 years old, please help me find out why i am in so much pain? I don’t have medical Insurance so i can’t really go to the emergency room. I worked 7 hours today on my knee and i have to work 8 hours tomorrow. I can’t do this.

Doctor: