It really depends on the doe. I have rebred a doe when she had a 4week old litter she was still nursing. I have rebred a doe a few days after losing a litter. Some of my does i give a few months in between litters. If your doe is at a good weight and wanting to breed (readily lifts for the buck) then go ahead and breed her.
I choose to re-breed at 5 weeks ,[because I choose to "not" have grow out cages , and I butcher at 8 weeks] but as AmberRae mentioned above ,there are other things to consider - make sure your doe is not "worn down" too much from nursing.. before deciding to re-breed her
In colony mine weaned at 4 weeks and had the next litter. If they kept condition I didn't interfere. Since both summer heat and subzero winters make it hard to breed here they often had around 3 back to back litters, a couple months break, and repeat. I did have a doe who hated to take a break and could keep 10 alive summer or -30f. She'd tear down hardware cloth barriers and get very moody if I didn't let her breed so she had near constant litters for years. Her coat didn't look great building those winter nests some years but she was still in great condition when I decided not to keep her anymore at probably 5 years old.
Now the Netherland dwarf rabbits frequently needed a several week break after weaning to recover coat and body condition.
If she's in good health you can rebreed now (or when the litter is 6 weeks old, but if you're saying you already sold them, Im assuming it's past that)