Hi, reddit users. This is my first ever time posting on reddit and English is not my first language. So, please be kind. I am 17 and currently in 12th grade. I don't know how it is in other countries but in my country, we have to choose a stream in 9th grade. I chose science stream at that time  because I didn't know I would end up like this. I was never good at maths which has always been a disadvantage for me. I practiced so hard for 3 years to get over this problem but it didn't change anything. No matter how much I practiced, I somehow ended up forgetting everything at the exam hall and even had a panic attack in the middle of an exam one time. I started feeling unworthy and anxious all the time. One thing led to another and I slowly started losing interest in all subjects. I have  entrance exams next year and even though I should study hard I simply just can't focus. I feel like my future is unsure. Now I am anxious all the time, I cannot sleep at night. I cut myself with my pen alot. Every time I pray to God, I pray for my demise. I even tried to commit suicide by chugging half a bottle of cough syrup and 3 sleeping pills. I just don't know what to do.
 ps: I told my parents about it. They don't believe in therapy. Also, I live in a third world country. So, it's pretty hard to find a good therapist.  Any advice would be helpful. Thank you.