How to complete my credits for back degrees?

how to complete my credits?  I have a total of 96 credits only from 1to 3rd year.  I m a BSc student.  I should have 132 credits to get my degree.  But I have already done my registration for 3rd year this year.  Now,  how am I supposed to earn the rest of the credits?  Plz, help. I don’t want to spend one more year for the degree.  I m a June 2018 cycle student.  Plz someone clear my confusion.