I'm sorry that you have been waiting a bit for a response to your question.
I think the issue may be that your question and description of Poppy's condition is a bit confusing.
It sounds like Poppy is very weak, refusing to eat, but will drink if you take her bowl to her and is lethargic.
Can Poppy walk normally, but simply doesn't seem to want to or seems too weak to do so?
When you says she "had a very bad season bit of clotting" did you mean that her heat cycle was abnormal and that she was passing more blood clots and bleeding more than usual?
An increased vaginal discharge can indicate endometritis, which is due to a thickened, abnormal uterine lining. This wouldn't necessarily be dangerous for her, but it does indicate that she likely has abnormal fertility because of her thickened uterine lining.
Another reason for an increased discharge which is much more concerning can be a uterine infection called a pyometra. Pyometras can rupture, causing peritonitis and/or the infection can spread to her other organs leading to abscesses in her kidneys, liver spleen and even her heart valves. The toxic metabolites from the infection can affect her appetite and can cause her to drink lots of water as the infection progresses. Thus even dogs that feel nauseous and refuse to eat will continue to drink water.
Early on the symptoms of an open pyometra and endometritis can be very similar as long as the pyometra is draining. That is because if the infection is draining she may not feel the effects of the bacterial toxins as quickly as if the infection was closed in and the toxin levels build up more quickly in her uterus and bloodstream. If the infection is closed, meaning her cervix closes so the infection cannot drain the toxic metabolites of the infection build up on the blood stream more rapidly, so those dogs feel much, much worse.
Antibiotics alone do not work to treat a pyometra as they have poor penetration into an infection filled uterus and do not address the pool of infectious material and toxins in her uterus. We sometimes use prostaglandin injections and combination antibiotics in dogs that have an open pyometra and that owners want to breed another time, but the success rate is variable. And even if it works if she isn't bred successfully on the next heat the chances of the infection returning are very high. At her age it is unlikely that she would be a good candidate for breeding anyway if she has a pyometra.
Ideally she would see her veterinarian for an examination and to check her vaginal discharge to try and differentiate between endometritis and an early pyometra. The sooner that she is examined the better as if this is a pyometra the sooner that is addressed the better chance she has of doing well. Treatment for a pyometra is stabilizing her with intravenous fluids and antibiotics and surgery to remove the infected uterus. The longer that you wait the more opportunity this infection has to spread and the more difficult it will be to save her.
Because her appetite is off, she is weak, and she seems to still have a drive to drink more water, or if she is running a fever (rectal temperature greater then 103F) then this probably should not wait, she should be seen by a veterinarian as soon as possible.
Please let me know if you have any further questions.