Yes it is known that antibiotics of penicillin group of drug can interfere with the effectivity of birth control and can make it less effective. As you have take a high dose of amoxycillin, it is advised that you may practice additional barrier contraception for at least 2 weeks from now.
You may experience some spotting or blood tinged vaginal discharge which could be a withdrawal bleed during this cycle after a week or so.
I hope i have answered your query,
wishing you good health,
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