Ups and downs...what is wrong with me?

Im new to the group and been having a hard time lately. Ive never felt like this before, a shell of myself. I cant remember the last time I genuinely smiled at something as opposed fake a smile because I knew it was the right time to smile. This leads to my question...is it normal to sleep 18 hours of one day and the next feel almost to normal?

Yesterday, I could barely function, didnt want to get up, didnt want to leave the bathroom after my shower, was an effort to make conversation, didnt want to eat, the 6 hours I was awake seemed like the longest day yet. Today, up, out shopping, doing things around the house, not ready to cry at any moment...what is wrong with me?!?!?