If they only dosed her once she will probably still have worms. She needs to be dosed at least twice with an all around worm medication to get rid of all types of worms. I'm sure the vet will be able to give you a good one for her. Meanwhile you could check her BM's to see if there is any evidence of roundworms. They are long spaghetti like uglies. Also check her butt to see if you can find any tape worm segments. They literally will break off in segments and stick to her fur. They resemble a grain of rice or a small flat whitish segment. The kitten may throw up roundworms too. You won't miss them if she does.
Other than that the vet will know what to look for. A pregnancy seems unlikely at her age but weirder things have happened. I would be booking a spay pretty quickly if she does turn up pregnant. At that age she would never survive a birthing.
Assumptions do nothing but make an ass out of u and me.
We can stick our heads in the sand for only so long before it starts choking us. Face it folks. The pet population is bad ALL OVER THE WORLD!