Hi
Sheer blood counts as an emergency; bloody urine does not. The intense red is more likely caused by a natural dye called porphyrin, which is characteristic for the onset of a urinary tract infection, whether that is a sterile (the old name is interstitial cystitis/IC) or a bacterial (baterial) one. Symptoms for either infection can take a few days to manifest fully. At the start it is all rather hit and miss.
As your girl is still eating, this is not a life or death emergency. Any sheer bleeding from the anus should also be checked in sows, in case it comes from the urinary tract but unless there is persistent bleeding or a large amount (which this isn't) it can wait until tomorrow.
See whether you can get one of the free slots for the day when you ring up your vets first thing tomorrow morning. Please switch from weighing once weekly on your normal kitchen scales to weighing first thing in the morning before feeding for best day to day comparison. The poos can only tell you what has happened a day ago; the scales will tell you how much a piggy is eating now; looser poos can be a symptom of pain or lack of hay intake. Keep in mind that over three quarters of what a piggy eats in a day is hay, which you cannot control by eye.
Here is some helpful information about problems with the urinary tract:
Wiebke's Guide to Pees and Stones
This guide explains the different methods you use for health monitoring and weight checking your piggy and what each method brings to the table so you can assess and monitor any weight loss or illness much better and can put it into the correct perspective.
Weight Loss Explained: BMI, Weighing, Poos and Feeding Support
All the best!
If there is a sudden problem (which I don't expect), here is our emergency care collection to make sure that you have access to all the necessary tips and practical information as we are late evening now and going into a weekend.
Emergency and Crisis Care as well as Bridging Care until a Vet Appointment