I had a one night stand and now im so scared i...

Dear Customer
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Are you protected from pregnancy ?
having pregnancy need many factors to make it happen , such as timing and ejaculating inside , besides you have took OCP medications on the following days , so you are unlikely to get pregnant , but anyway , you have to do the following :
1. take a home pregnancy test in the last week of your period 
2. avoid unprotected sex 
Are you pretected from STD ?
if your partner didnt use condom , then you are not protected 
Why does your vagina starts itching later ?
vagina itching is a sign of vaginal infection , which could be an STD 
- dont worry , most of STD is easily and simply treated 
Treatment of vaginal infection :
1. visit your gynacologist doctor to do the medical check for  
2. pay attention to your personal hygine 
3. avoid direct contact to other by sexual intercourse or touching to prevent spearding the infection ( if existed  )
4. use condoms and protecting tools during sex 
4. in case of bacterial infection such as Trichomoniasis  , you may use Metronidazole for 2 weeks course  topically or orally 
5. in case of bacterial infection such as chlamydia , you may use azithromycin or doxycycline for 2 weeks course  topically or orally 
Needed medical tests :
1. routine clinical check by doctor 
2. vaginal discharge or effected area bacterial culture
3. urine cultural check 
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Kind Regards