Hey,
You are good at both Biology and Mathematics but you don't want to be a doctor and that is completely fine. There are various fields which are worth exploring other than MBBS. Since you have Mathematics,you can go for Engineering if technical fascinates you. You can go for B.Sc courses in subjects like Physics,Chemistry,Zoology,Botany,Biotechnolog,Life Science,Agriculture and later be academician or scholar.As you know that a doctor can't treat a patient all alone,he needs medicines and other things so you may go for paramedical fields that are in huge scope. You may go for Physiotherapy,Pharma sectors etcetera. You may even switch your stream and pursue Bachelors in Humanities. You may go for BBA if you want to make career in corporate sector.You may go for BCA or Law.To be a lawyer you may go for five years integrated programme CLAT or three year programme of LLB after your Bachelors.
It all depends on your calling and interest.
Hope this helps.
Good luck.