Mucus plug?

Hi guys.

Im currently 31w2d and yesterday i had a yellow and mucus like discharge.

I didn’t take a photo and i wouldn’t want to post it anyways, but it was weirder than before. It was more intense, and really look like when you are sick and blow your nose.

Sorry if it’s disgusting but i don’t know how else to explain.

I texted my doctor and he said that i should let him know if it happened again until friday.

It didn’t happen again today, but i got a little bit worried.

Could it be a part of the mucus plug? If so, what happens next? Early birth?

If not, could it be an infection?

I’m a first timer so i don’t have a clue what’s going on.

Thanks in advance xoxo