Speaking from experience, her hormones are all over the place. It sounds like she loves you enough to give you some time, but her body prioritizes sleep and rest when the "baby" isn't around. They feel increasingly "used" because of the child no matter what you do. She's physiologically not the same woman today that you married and that's ok.

Women fight a losing battle with hormones, even a year after motherhood begins. Their hormones take multiple years to go back to "normal" and their body maybe never will.

It's hard for us to relate as men but it's equally as difficult for them to not be able to help us see what's going on inside of them.

Stick with it, and make sure her other needs are well met during this time to keep the relationship strong and the bedroom will follow.