Ok. First I am sorry that this is happening. Second, The vet might not have known, if she was VERY early on in pregnancy.

When I took in AbiGail, she was pregnant. I spayed her anyways, because she was only 5 months old, and I had 15 other cats to tend too.

It should be ok for her to have been dewormed. I doubt it will cause problems.

You can tell she is pregnant by a few things. Her belly getting larger, her consuming more food and water, but the only SURE way to know is to have a vet check her.

NOW with that being said... I dont know your financial situation... BUT you have to make a decision and fast on whether you will let her have them or not. If you arent, I would suggest taking her ASAP to confirm whether or not, and then set a date to have her spayed. It wont cost much more than a regular spay. Mine was about 100-150 more, BUT my vet is very high cost compared to other states it seems.

GOOD LUCK! Kt and kitties