OP, this is natural, a blip.
After I chucked twunt out after 20 years of marriage and three kids, I was fine for about a month. I filed for divorce, made all the phone calls about utilities and stuff, told everyone, supported the kids and kept going to work.
Then I was in the middle of town, and I heard a song in a department store and boom! It hit me like a ton of bricks. I made it home, bawled my eyes out, shook like a leaf and just fell apart.
It happens, it's like reality hits. But the next day I was ok again.
All I can say is accept it, ride it out, and tell yourself it will pass. Because indeed it will.
It might happen again, so accept it, ride it out.
It's all part of the process, it's like grieving, the stages randomly come and go, acknowledge them, look after yourself.
The good days will be more frequent, the wobbles less awful
Baby steps, treat yourself as you would your best friend.