4 year old with what seems like Leukemia symtoms..

My poor kid was tired and pale and complains of headaches and belly aches. I took her to the doc and they did a CBC and found she is anemic. Her WBC count wasn't too bad so they didn't really suspect cancer. Well today while helping her put her pj's on I notice petechiae under both armpits. Not a lot but probably a dozen or so under each armpit. (I have seen it before when my son was very sick coughing and puking, he got it on his cheeks) ANYWAY should I be concerned? They gave my iron supplements for her and sent me on my way. I just have this gut feeling like something else is wrong here?:confused: Of course all my research says maybe Leukemia but that REALLY scares me and I don't want her to have painful tests if Im just overreacting..
THANKS!