LOL, Deal with It
You know what they say when you don’t know something—pretend that you do. That appears to be the case with this mother, who probably read LOL somewhere and thought it meant lots of love. No, ma’am, that’s not what it means. And what pains us is how easy you can find the answer if you search on Google.
The poor, poor OP was just venting to her mother about having a crummy day at work when, all of a sudden, the mom blurts out laughing right in her face. We can’t help but LOL at the OP’s misery.