6 months old gets stuck in the mini crib slats and hits her head

Dear mommies, I'm seeking advise. My 6 months old baby started waking up more frequently due to getting stuck in between the wooden slats or just hitting her head against them.  She moves a lot and also ends up on her tummy and getting her feet  stuck. She sleeps in a mini crib. Should we get a bigger crib? I was thinking of getting a breathable mesh liner, but our pediatric clinical advised us against it. Any advise would be recommended?