I Have Been Taking Amoxicillin 875 Mg Since Monday, March

I have been taking Amoxicillin 875 mg since monday, march 7th and it is for 10 days. March 3rd I ended my Birth control pills and this week I was suppose to get my period around march 7th or march 8th. It did not come. I know the Amoxicillin can delay the period, but on this friday, March 11th, I should start my new birth control pack. Should I still start it even though I have not have my period? I have not missed any pills and I take them at the same time that I am suppose to. Should I be worried, and is there a need for a pregnancy test. I sometimes have unprotected sex but since my last period, the ejaculation has been on me not inside me.