Is my cat going into labor?

I woke up around 2 in the afternoon and ever since then my cat has been purring and rubbing her face on me, which she occasionally does for a few minutes at a time but she hasn't stopped and she keeps making a sound like mmhm as if someone's calling her name. She won't let me touch her bottom half unless im rubbing it. And she won't lay down her usual lazy way, which is on her side with her feet out, she's sitting on all 4s and her but is slightly raised. I've only had her for 6 months but she's fully grown now, and she went through heat. She's gotten out of the house 3 times I don't know if she could've gotten pregnant. And just last night i put some Advantage on the back of her neck where she cant reach, could she have licked it and gotten poisoned? My mom thinks she has to take a poop or something, but i doubt that's it.