Hello Amanda, I'm Dr. Deb and I'll do my best to help you today.
When it comes to loose stools in a cat, there are any number of reasons why this might happen:
Stress (as you mentioned), internal parasites, Inflammatory Bowel Disease, changes in diet...just to mention a few.
And, while blood can be alarming, it doesn't necessarily have to be concerning since it usually is secondary to an irritated colon and nothing more. Just about any one of the conditions I mentioned could cause it.
Just to be on the safe side, I'd probably have a fecal evaluated, even though she has been wormed. Some cats need multiple deworming before internal parasites are eliminated.
As to what you can do for her which may be helpful such that a vet visit can be avoided (and thus adding to her stress), the following are my suggestions:
1. Feed a bland diet of boiled chicken. This won't be nutritous but several days won't be harmful. You could also try human baby food but avoid those with onion or garlic in them.
2. Probiotics can be particularly helpful in a situation such as this. Not only can they help with gi issues, but they have been shown to help when cats are stressed, too.
Forti Flora is a brand which I like a lot and may be available at local pet or grain stores.
3. Unfortunately, I wouldn't advise any over the counter anti-diarrhea medications since cats can be very sensitive to these drugs. They might cause more harm which is the last thing we'd want!!
4. If the stools persist in being loose, then she may need stronger anti-diarrhea drugs which would have to be dispensed by your vet.
5. But, if her stools start to improve, then I'd slowly introduce regular cat food back into her diet. If they become loose, then she may have Inflammatory Bowel Disease (or something similar) and would need to be on a more hypoallergenic diet.
Ones which I recommend include: grain-free which works well for some cats, or Natural BaXXXXX XXXXXmited Ingredient Diets, Nature's Variety Instincts line, Evo duck or venison, or Nature's Variety Frozen Raw Medallions (I recommend that they be zapped in the microwave for 10-15 seconds on each side).
As to her anxiety/fear, I don't know if you've been using Feliway or not but it may be something to consider. This is a natural pheromone which is intended to reduce anxiety and instill a sense of calm. It comes in a diffuser which plugs into the wall or a spray; it can be purchased at most pet stores but is also available on the internet.
I hope this helps. Deb