I am in classXII but now I am regretting myself that I have not studied physics and chemistry at all in class11 but good thing I did was studied biology. So what should I do to complete along with preparation for board so that I would come out with flying colours sir suggest something. ?

@ abhinab , 
right now as u are in 12^th then, revise your 12^th topics regularly in each day and make sure you do it very well so that if  NEET asks any question with reference to class 12^th , u can answer everything correctly as its your strong part . 
and i appreciate your effort of studying biology in class 11^th as a medical student . 
and as u knows biology have the most weightage in aipmt / neet exam . 
now , what u can do is to alert the wekend to read the 11^th topics , 
in wekend only read the notes and the formula from ncert , if u have not made note , thats already avaliable with askiitian . 
and solve some question from previous year paper if time allows you to do it . 
thats it , donot stress yourself , beacuse with stress , u cannot do your maximum . 
HOPE IT CLEARS YOUR DOUBT 

ALL THE BEST .. 
IF ANY MORE THEN PLZZ ASK ..