I have never heard of a psuedo pregnancy in a guinea pig. I'm assuming they can happen in piggies but i have never heard of it. If she is passing blood from her gential area, it will either be a UTI, or a uterine infection (or possibly a vaginal infection but i doubt so) i would assume. I would get more of a comprehensive diagnoses if she doesnt make an improvement, and i would keep a very close eye on her. Uterine infections can be quite nasty if not treated with strong antibiotics, and in some cases spaying in the only and best opition. Not trying to scare you... just putting my thoughts forward. Has your piggie ever had pups before? and is there any chance of her being in with an uncastrated boar recently?
I would suggest if you have no improvement in the next few days, get more of a diagnosis to rule out uterine (and ovarian) problems. By maybe at least a conscious xray, and/or an ultrasound.
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