Cutting myself

Last night i cut for the first time ever in my life,i dont know how it felt i wasnt with it. I was walking to work and i saw a peace of glass on the floor,so i went into the woods and slashed parts of my body with the glass,i cut my neck,chest,arms stomac and leg tore my clothes off  then i phoned the police and said id been raped again,which i hadnt i have no idea why i did it or why i said the most awfull on earth had happened to me again,i said a man had attacked me with a knife after a few hours i came clean to police and told them i lied. I broke down and was in a mess, the officer could see i needed help and advised me to see a mental health officer, i feel so ashamed with myself and hate myself right now,i lied to my ex boyfriend and he was devastated, but wen i told him the truth he as been fantastic,he said e will help best way he can. Ive been to the doctors today and changed my anti depressents as the doctor thinks it was them that caused my mania, she also refferd me to a mental health team. I feel ashamed and hurt