Hi there,I know how you feel,I'm like this all the time the ups and downs.
The meds especially trying new ones can leave you feeling so drained and tired,I never feel wide awake if I'm honest I'm always tired. Being a parent myself there have been a few times where I've put a dvd on and spread toys out on the floor to keep the kids amused and yes they were safe as there's nothing to harm them but I felt guilty.
I felt they were missing out because of my mental and physical health,then I spoke to my therapist who told me that I should never feel guilty or a failure as its not my fault also everyone has off days.
Your not a failure I can tell by your post your a good mum otherwise you wouldn't be worrying.
Am always around if you want to PM me
Take care
Jk