Weird discharge

I'm currently 28w4d, woke up last night to go to the bathroom a few times, but when I wiped, I saw some clear, jelly-like consistency coming out. Similar to the gel they use for ultrasounds. I don't know if it's relevant either, but I vomited quite a lot before the seeing discharge.

It wasn't too much, but surely not something I've experienced.

I'm really nervous, as my OBGYN told me to come in, no explanation.

Any thoughts, ladies? I'm really nervous.