Prolonged Vomiting In Pregnancy, Back Pain, Leg Pain, White Discharge. Need Information On The Scans To Be Taken During Pregnancy

Hi Sir, I had my last menstrual on january 19, now i completed my 4th month of pregnancy, This is my first pregnancy so i am having lots and lots of doubts, i confused myself a lot. Till now i am having vomiting ,from the starting itself it slighlty occurs in the morning session,and at night. i adont know why it continious till 5ht month? And i am working women, i used to walk and travel by bus,bike .. does it affects my pregnancy? i am having back pain ,anf leg pain often,more than that leukorrhea discharge is there,thighs are paining.. does it affects my pregnancy? what are the SCANS to be taken at which months it would be taken? how can i check that my baby is not having any dis ability? please help me sir,.... i cannot breathe normally also