Possible leukemia in 4 year old?

Right now we are waiting on some test results to come back for our 4 year old son, but I just can't rest so I am trying to get more insight. About a year ago our son began developing petechiae. I never thought much of it until March. He was running a fever, and had a lot of petechiae on his face, neck, and arms. We took him to the doctor who ran a CBC and everything came back normal so we left it alone. For about the past year he also began having nosebleeds, and night sweats. I didn't worry too much about the nose bleeds because they began closer to the winter months, and as for the night sweats, his father sweats some at night so once again I dismissed it. Over the past month and a half the nosebleeds have increased significantly, and he is waking up in the middle of the night drenched in sweat to the point that I have to change his sheets. I took him to the doctor again today who ran another CBC, as well as some other blood tests, and a tb test. I know my doctor does not want me to worry if it's nothing, but seriously... how common are all the issues to develop together? When they put the tourniquet on his arm for the blood draw, he immediately developed petechiae on that arm. I am really worried, and won't get the test results back until Thursday. What does this sound like? Am I out of my mind for freaking out right now?