My dog has green discharge coming out of her nose, her poop is like brown tar, and her pee is almost brownish gold. She is so week she can't even stand herself up because her back legs won't push her up. She has been to the vet twice in the past two weeks and they did blood work and can't find anything wrong with her. She has been on two different antibiotics which gave her sores in her mouth and nose and gave her a nose bleed and was on an antiinflamatory but now we took her off all of it and at least the swelling in her legs has gone down, she is retaining water in her feet and legs. Any idea what this might be?

Did the vet give you any indication of what could be going on?
Hemolytic anemia? Kidney or liver disease? Bleeding disorder?
I would strongly consider gathering my records and seeking a second opinion, even having your vet refer you to a specialty hospital or veterinary teaching school (if there is one in your area)

Do you know specifically what testing was done?

Vet did basic blood tests and said there was no indication of any tick-born diseases or anything for that matter. Some elevations for some bacterias so he perscribed antibiotic and anti-inflamatory. Went back a few days later, she wasn't as weak but was now sneezing like crazy and had sores in her mouth. Lymph nodes in throat were size of golf balls but no other inflamed lymph nodes. He perscribed a different antibiotic instead, the sores went away, the lymph nodes are no longer enlarged, but she still has water retention in all four legs and is very weak, does not even get up to greet anyone, and has to be helped up to go outside.

Obviously none of us can diagnose anything on line, the fact is that your dog is puzzling even your vet.
How old is your dog?
The weakness, the tarry stool, very dark urine, and nose bleeds seem to suggest a bleeding disorder of some sort. Of course that is only one of many possibilities, and a guess on my part.
Is she heartworm negative?
Has she been vaccinated against distemper/parv/lepto throughout her life and kept current?
Is there anything that she could have gotten into, such as chemicals, medications?
I'm sure your vet has already covered all of these questions, but sometimes thinking about them again will jog some thoughts or something that you have forgotten about.