I'm 13 and i smoke pot?

Now usually when i smoke i'm able to keep it hidden from my parents. But yesterday morning i went into school high as hel. I don't usually do this. But my teacher kept looking at me wierd, she knew i was high. She pulled me aside and asked me if i was on drugs or if i had taken any medication that day. I lied and said no, but she sent me to the office and i got suspended for coming to school high for 3 days. Of course they had to contact my mom, and now my mother is going crazy. She's crying and lecturing about me about how i'm a failure and will never suceed in life now. And how i have no future ahead of me. She wants to send me to some rehab camp. What should i do? Please help...please