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The chances vary depending on the type of pill you missed.
If the 3 pills you missed were one that needs to be taken for first 21days, then there are some chances of pregnancy
. If it was one of the 7 placebo pills, missing the pills do not affect the chances of pregnancy.
That being said, the bleed you had on Sunday is probably withdrawal bleeding and such as bleed reduces chances of conception significantly.
Hope this helps.