mucus plug at almost 29 weeks?

I’m 28 weeks 5 days and I wiped after using the toilet and I noticed something stringy so I grabbed a mirror and more toilet paper and pulled out a long thick sticky jelly-like yellowish/clearish clump. it had a tiny streak of white

a minute later I got on the toilet and flushed with warm water and saw in the mirror more was coming out so I pulled more of it out

no pain/contractions, my baby is still doin his do, kickbox practicing on my organs and whatnot so I know he’s fine.

I have a doctor appointment tomorrow in the morning for a glucose test and anemia test should I ask her to check my cervix or should I not worry and just look out for any symptoms of labor?

im so worried im not even 29 weeks yet it’s too soon for him to come out I’m praying he stays at least another 8 weeks or so 😭

will my doctor even be able to tell or not? like can she determine if based on if my cervix is open or not? and what if it’s open what does that mean?

im so stressed pls help😭😭😭