I dropped a class because there were so many women in it.
Are you serious? Why would the amount of women in a class make you give up on it?
I feel stressed when there's too many women in the class.
You shouldn't be judging people on their gender . That's not something that they are able to control so it's not something that you should judge them on. Have you thought about trying to make more friends of the opposite gender so that you get used to interacting with them?
Nah. I don't want to bother.
You need to be able to interact with women if you want to be able to navigate life successfully. Women are people just like you, and you shouldn't judge them based on their gender. If you can't bring yourself to be friends with women, you should talk to a therapist about this issue.