It's possible. Try not to worry (easier said than done , i know). You cant change it now unless you wanted to take the morning after pill, though i dont know if that would be recommended so soon after birth as it can make you feel sick. Talk to a dr if you're concerned.
Its unlikely, but not impossible. I know two two women who had babies within 10-11 months of having a baby - one of them even managed to have them in the same year - one in January and one in December!
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