Well first off are you pregnant?
If so see your doctor immediately if your concerned about an infection or STD.
If you are not , I'd still suggest asking your doctor.
We can only give you advice, and cannot diagnose you with anything.
Itching can be from a number of things, dryness, change in discharge and many more things.
Your best bet is to make a doctor's appointment a.s.a.p.
Good luck... and please be more careful and protect yourself.