No one has received my wedding invitations

I’ve mailed out invitations nearly 10 days ago and not a single person has received one. Not people in my town, zip, or state. Certainly no one out of state. They’re wedding invitations so, obviously, I didn’t pay for individual tracking. They were weighed and stamped appropriately, the addresses were clearly written, and the return address is a printed label. Is USPS just that backed up? What should I do? What CAN I do? I feel sick because we spent a lot of money on the invites and postage.