hi, Jane.
I simulated a part of your circuit and it turns out that your magnitude vs. frequency is way far compared to the figure 5 of your reference. I've noticed that the value of your RG is 56ohm compared to the 15ohm on the app note.
the magnitude level was improved when i tried to change R109 (56R) to 15R, and for the load, try to remove R127 (75R) and R116(150R).
Attached in this thread is the simulation i made based from your circuit. Kindly check if I put the right components in the circuit simulation. Try tweaking some components and see improvements.
regards,
ahbie