eating less and spitting

Hi everyone, my little girl is 6 months old today, and over the past two weeks, she learned how to spit. She does this randomly when she wants to play, but also when she no longer wants to eat or drink. We just introduced solids 1.5 weeks ago, and she only eats about a tablespoon per day. She used to drink 30 ounces of breastmilk per day but since starting solids she only has about 25 ounces. She refuses to eat her normal amount at each feed, and just starts spitting and playing. She also started to spit up a little more than usual recently. Not sure why she's doing this, but wondering if anyone else experienced this? She's on the smaller side to begin with so I'm concerned she is eating less and spitting up part of what she does get down.