Rabbit random bleeding

We have a 2 1/2 year old indoor rabbit. Never been around other rabbits. Couple of weeks ago I noticed some blood on her underside just one drop. I called the vet. They did a X-ray and ultrasound and found nothing. Had us just keep an eye on her. Two weeks later she peed on the floor and I found blood in it. I took a urine sample to the vet. They treated her for a bladder infection from not drinking enough water. So she's on antibiotics, under skin water treatment and no more pellets only water based veggies. She's been doing great. Until today when I found more blood and more than before. She is acting completely normal. Running around the house and eating like crazy.

I'm looking for direction. I will be taking her to the vet again in the morning but I'm looking for thoughts to make sure we are headed the right direction.

If she was acting sick it would be totally different however blood is never normal. Please help

Did the vet actually find blood and bacteria in the urine sample?

If they didnt rabbits are known for having redish coloured urine.

If they did then yes a trip back to the vets is likely needed.

What are these veggies youre feeding? Were crystals or sludge in the bladder found? Does she have a water bowl or water bottle?

Sludge urine I don't remember what she said about bacteria.
We are doing celery, cukes, spinach and lettuce and carrots

If it is actual blood you are seeing and not just reddish orange urine from plant pigments, a UTI is still possible, especially if your rabbit does have bladder sludge as this will continue to irritate the bladder as long as the sludge hasn't been flushed out. The UTI could either be reoccurring or the previous antibiotic wasn't effective. If so, the vet may need to do a urinalysis to verify blood in the urine, and to try a different antibiotic, possibly doing a culture to find out what antibiotic to use. If there is still sludgy sediment in the bladder, this may need to be flushed out and your bun put on a low calcium diet, and possibly meds and regular sub q fluids to help prevent calcium from building up again.

If it's not a UTI or bladder sludge causing the blood, some other possible causes could be kidney issues, a bladder/kidney stone that was missed on the xray, or if your bun isn't spayed, uterine cancer is a possibility.
http://www.medirabbit.com/EN/Uro_gen_diseases/Differentials/Blood_urine.htm

http://wildpro.twycrosszoo.org/S/00dis/Miscellaneous/Cystitis_Ele.htm
http://wildpro.twycrosszoo.org/S/00dis/Miscellaneous/HypercalciuriaRabbits.htm
http://wildpro.twycrosszoo.org/S/00dis/Miscellaneous/Urolithiasis.htm
http://wildpro.twycrosszoo.org/S/00dis/Miscellaneous/UterineAdenocarcinomaRabbit.htm

She's still on her antibiotics for the bladder infection. Urine is clear most of the time she pees. Except this morning when I found the blood like I had previously and then she pees and it's kind of mixed in there. It doesn't look like the picture you linked. She's not fixed but probably will be after this. She's has no other signs of the cancer issue aside from the bleeding. And it extremely random. We are headed to the vet in the am.