My husband has Stage 4 Lung Cancer that has spread to his brain. He has ten tumors in his brain, one that has grown to about and inch and a half in diameter.
I don't know how all brain tumors grow, I suspect some grow slow and some fast. With my husband, we could see the effect the tumor was having on his body every day. He had major neurological symptoms like complete numbness that spread all the way down through the right side of his body. He lost the ability to walk straight. He lost the ability to control his right hand well; he'd struggle just to put food in his mouth. The docs did radio surgery on this biggest tumor and my hubby has improved a lot.
I am also afraid of brain tumors; however, I think you'd be seeing some serious indicators by now.
Take care of yourself. Stress does amazing things to our bodies.