Also* mucus plug is thick and kind of stringy, everyone is different, some have bits of red of blood in it
I agree with @leisharn I lost parts of mine back when I was about 24 weeks.
No you're very wrong littleperson96.... You can lose bits of your mucus plug throughout your whole pregnancy and it will just keep rebuilding, you can also lose your whole mucus plug from the end of your second trimester and anytime throughout your third, it does not mean you are in labour, you can lose it weeks before you go into actual labour, is a sign that you're close though :)
Your mucus plug wont come out untill your in labour ready to deliver, your bag of waters will most likley break before your mucus plug comes out. Discharge is normal when pregnant, although if you notice more than their should be you should consult your dr, o.b or midwife.
Yellow/Green is most likely discharge and might be a infection might want to call your doctor.