Mama, yellow-greenish discharge during pregnancy can be normal sometimes, pero since you're already worried, mas better talaga mag-check with your OB para ma-confirm lang na lahat okay with baby, better safe than sorry, especially at 33 weeks na. A few of my mum friends had similar concerns at that stage and their doctors just did a quick swab to rule out infection, walang hassle, so don't stress too much pero don't skip the visit either!