I would personally be demanding a swab to be done to make sure there’s no infections. I’ve had discharge but it’s always milky white.
I would definitely be a bit concerned about the colour, as even with thrush it usually is increased discharge but not with a darker colour, but it is typical late pregnancy to have a bit of blood/brown tinged. I would put in a fresh pad now and keep it to take in to the hospital as they may want to see it - that’s what happened when I thought my waters had broken, they wanted me to wear a pad to be seen so I just went in one rather than waiting to be given one there. I think it is most likely nothing, could be cervix irritation as getting closer to delivery. Personally, I would probably give them a ring, they can advise over the phone if they think you should come in just because it’s urgent line doesn’t mean you always have to go to hospital (it’s urgent ADVICE for a reason) Better to be safe and go in to be checked! Just a pre warning (but i’m guessing you’re fine with it as you’ve had thrush) they will probably want to do a speculum swab to have a look and test for infection/waters❤️
The colour looks odd to me - ask for a swab and scan
If you are worried show your midwife it also could be loosing your mucus plug so I’ve heard, if it has an off smell or down below is stinging it could be an infection so I would see triage x