You need to check your status by ordering a self-test kit from the Sexual Health team. You can order online at letstalkaboutit.nhs.uk. This will be posted to you in plain packaging for you to discretely complete at home.
If you have any symptoms of a sexual infection, you should call the Sexual Health team on 0300 300 2016 to request an appointment.
Information on sexual health can be read at the NHS website