Five year old making up injuries/extreme school anxiety

My 5 year old has developed significant school anxiety and I don't know what to do. She comes from a long line of people who always feel a little bit sick or injured, especially when they have something scheduled that they don't want to do. I'm not being snarky, they genuinely believe they are sick or hurt to the point that they will make themselves throw up or limp or collapse when they try to walk but if I took them to the doctor there would be no clear indication of illness. Anyway, she started kindergarten this year and after the honeymoon period she started having stomachaches or headaches or leg aches.

By the time we got to thanksgiving week, she was refusing to get on the bus, screaming and crying about pain in her legs (but forgetting which leg and switching, etc) and various other ailments.

According to her teacher, there was some incident where a substitute didn't line the kids up on time and their bus was missed. Since then she said my child has fixated on the bus schedule and will demand to be released from class early and panic and argue about missing it again. The teacher says since the bus incident the school injuries have ramped up considerably to the point that all the teachers are not able to get her to back down about her fever or leg pain or what have you and she refuses to participate in activities frequently.

At this point I can't get her to get on the bus so we are car riding but she is still fighting till the last minute. She repeatedly answers my questions about why she doesn't want to go to school with her hatred for the lunch options, PE, and being away from me. I have no indication that there is any negative person or incident that has occurred and the teacher is not aware of anything either.

We are about 18 months past a divorce and moving to a house without her dad, but we live near him and she sees him multiple times a week. Right now she won't go to his house either because she doesn't want to leave me. As an attachment parent, I want to just pull her out of school and keep her with me, but I don't know if that's the right solution, especially with the behavioral elements of all this. I know I probably need to get her to a therapist but she has Medicaid and I expect my options are pretty limited. Thoughts, suggestions?