Has anyone ever experienced this? I wake up at 7 am and go to school …

Has anyone ever experienced this? I wake up at 7 am and go to school with my kids, I feel good, everything is fine. If I sit down or lie down, it just knocks me out until 11 am, I can't open my eyes, some kind of weakness comes over me... if I get up, then the same thing happens...this period until 11 am I just fall asleep, after that everything is normal...but I seem to sleep well at night...what could be wrong with me? Maybe someone has had this before? Thank you for your answer.