Hi jbake37,
There are some suggestions for a mattress that is too soft in post #4 here that may be helpful.
I’m not sure how thick your topper is but it may also be part of the problem as well. You may do better without the topper or perhaps with a thinner topper.
Stomach sleepers tend to do better with a firmer mattress than back and especially side sleepers to prevent the hips/pelvis from sagging into the mattress and sleeping in a swayback position and adding a softer topper on top of a mattress that already has some softer materials in the comfort layers could easily result in comfort layers that are too thick/soft for you.
Phoenix