inguinal hernia Surgery- muscles are still week

Dear Doctor,
Hello,

i had a hernia Surgery 2 years back,and it seems fine now,but i felt that my stomach muscles r still week ,
how much time it will take to be same as it was before operation,
if i push my stomach muscles tightly i feel little pain
and i am also gaining weight only my tummy getting bigger

Plz Advice what i need to do,
do i need to do any exercise,
Thanks in advance
Name: amit
Age 25
Work: Computer Programmer
nationality : India