Dear Mom2Twins:
If I was you, I would come clean to my friends as soon as possible, and tell them just what you posted here. You told a lie and an unnecessary lie so.. correct the lie by telling them the truth. Do so in a way that shows regret but also respect for yourself (for courageously correcting your mistake).
Keep in mind that your friends are not perfect either. Maybe your correction of your own mistake will encourage them to do the same: with you and with other people in their lives.
anita