Need advice! Losing mucus plug/ cramping

Okay so I am 29 weeks pregnant now and was in the hospital last week with threatened preterm labor due to cervical shortening/ funneling and severe Braxton Hicks. Since then I am pretty sure i have been losing my mucus plug (Discharge is thick globs of yellow with blood once or twice a day). Starting to cramp now and have a ton of lower back pain but no contractions right now. I told my dr about the discharge yesterday and she blew it off like it was a yeast infection but I’m almost certain that’s not what it is. I just want to make sure I’m doing the right thing and can get to the hospital in time to get baby whatever he needs/ stop it if something is going on! Any advice is appreciated as I want to trust my doctor but am not so sure right now. TIA!!