This sounds rather hormonal in nature. Is it Spring in your part of the world?
Rabbits have a bit of an increase in hormones in Spring – even desexed rabbits.
If she is not desexed, it’s possible she can have a false pregnancy even though she is not around other rabbits. This can make female rabbits change behaviour and even go so far as building a nest and pulling out fur for it.

At this point when she bites I’ve been just placing a hand on her head because it makes her stop.

Is she acting aggressive as soon as you stop petting her?

Be mindful that an underlying health issue could be reason for aggression also.

Mmmm…. that is a place I would think fur would naturally become trapped. But if its a lot, that makes it more suspect. Can you see if she’s been pulling fur from around her hind end, tummy or chest?
If she is nesting, that would suggest her spay is incomplete. We actually have another recent thread in Behaviour section where this happened.

Does she have access to hay? They will often use some hay and paper to construct a nest. False pregnancies don’t last as long as the real thing. They are about 3 weeks compared to 4 weeks real gestation. A rabbit will lose interest in the nest they make and you can clear it away by that point.

When I pet her, she bites as soon as she realizes that I am not petting her anymore then she’ll get mad and flick her feet at me before coming back and asking for pets again. I don’t like the feeling that i might be being mean to her, but I don’t know how to make my bunny understand that she shouldn’t bite me.

That is not uncommon with some sassy rabbits! Communicating with their teeth… .
But you are right, you don’t want her thinking its acceptable to bite. The ususal suggestion is to let out a loud squeak if they bite, much like another rabbit might do. If one of my buns gets growly and bitey, I don’t retreat straight away. I try “stand my ground”. Because I don’t want to reinforce that aggression from them gets results.