First,you take it go to the doctor.
Then,see what the doctor say.
If your cat really get flea,then you have to tidy up your house and keep the messy away.
After that,you can go to the doctor again but this time tell him that you want to kill the flea and maybe he will put some medican on your cat.
Finally,ALWAYS no to put your cat to somewhere that is dirty like resterant.