Okay, thanks for the additional infomation.
When we see stool that is "jelly-like" and with fresh blood, this usually indicated inflammation in the colon or lower part of the intestines. The colon produces mucus normally and when irritated can easily bleed. If inflamed, the tissue of the colon will produce LOTS of mucus, which leads to jelly looking poop, and fresh blood is also often involved and of course can be quite alarming to see!
Colitis, or inflammation of the colon, is quite common, and can be related to stress, parasites, eating something unusual, a sudden diet change, etc. Less commonly, it could also indicate more serious issues, such as some type of infection, cancer, or toxin exposure. If you are confident your dog has not had access to toxins lately (such as rat bait in particular) I would not be terribly concerned about that.
When the gut is "off," it is common that a dog may not want to eat or drink for a short while. This is not necessarily bad, as they are giving their gut a chance to rest. But if they won't drink for more than one day, they need to be examined as they may need fluids so they don't get dehydrated.
In some cases, dogs get better on their own after fasting for 1-2 days. You can fast your dog at home (no food, water only) and then start boiled hamburger and rice in small quantities after that time. This is easy on their system. Again, if they are not willing to drink or they start to vomit frequently, or the bloody stool worsens while fasting, they do need to get in to the vet.
If they are drinking and/or eating and seem perky but the bloody/mucus stool continues, at least a stool sample needs to be evaluated for parasites and proper therapy may be prescribed. I treat many colitis dogs with a prescription medication called metronidazole, which usually corrects the problem.
Any other questions? I hope this has been helpful for you, and that your dog feels better.