Method Partial suspension hanging - why didnt it work?

[3FailedAttemptss]

Hey! :3 So I tried to kill myself today via partial suspension hanging >w< and I did so using the lace of a hoodie. It's about a meter-long string, quite thin and small. It's the only thing I could get my hands on here in the psych ward. I feel like I followed all the steps. I tied a double knot around a door handle, which is the only point I could have fixed a string around. I lubricated the ligature, I tied a slip knot, stuck my head in, and leaned forward. All I could feel was my jugular was being compressed but not my carotid arteries— I wasn't losing consciousness :( but it felt like my head was about to explode, my hearing was going and I felt like throwing up. I tried like three times before giving up, leaving a really visible red mark across my neck, which the staff then noticed. Now I'm on suicide watch T-T

I'm just wondering cause I have one more string that I smuggled in what can I do next time to make it work???