Is my hamster pregnant?

Okay, I Know this sounds wrong but my friend came over and brought her hamster over he was a male and the school needed baby hamsters for the children in the cl rooms at an elementary school is like 15 rooms so instead of buying 15 HAMSTERS! we decided to breed them. so we put the male in the cage and they crawled up in this tiny little space ship comportment and they started fighting we quickly took them out. we put them in a big cage and there where fine. 4 days later the started each other! WEIRD! 1 hour latter the male would climb up the space ship tube and the female would bite his and nip him up the spaceship! So we took out the male and the female has been making a nest and jumps a little and sneezes ALOT ! So the question is "Is my hamster pregnant??? Thanks for the help and concerns!!! :))))