My unspayed Shih Tzu is lethargic, not eating. Is she in heat or sick?

It's possible, if she is in heat and was outside, that a male dog came into contact with her. If she is now acting very ill or lethargic, it would be best to seek out veterinary care to make sure there isn't another underlying cause, injury, or illness causing her symptoms.

I can certainly understand being concerned about Tulip! Lethargy is a very general sign of illness, and it can be caused by systemic illness, infection, inflammation, or injury. I would keep an eye on her tonight, and if she is still acting this way in the morning I would take her into a vet first thing for a health check.

Drinking more than usual, loss of appetite, or vomiting are all classic signs of an infection if the uterus also known as a pyometra. These are more common in older dogs. These can become very serious and even life threatening if left untreated. I would strongly advise that you gave a veterinarian examine Misty right away.

Dogs can feel lethargic and not want to eat during their heat cycle especially their first one. However, this shouldn't last long. Vomiting is a bit unusual for a heat cycle. She should get a physical examination by a veterinarian to make sure she doesn't have gastroenteritis or pancreatitis.

Lethargy and diarrhea re not usually normal during a heat cycle. Most dogs will be actively looking to mate, alert, receptive and have swelling of the vulva along with some bleeding. If you are seeing discharge that is not bleeding, diarrhea and lethargy it is best to bring her into a vet as soon as possible.

Poor girl. Some dogs have a tougher time than others when it comes to their first heat cycle. However she does seem to bra late bloomer as most dogs have their first heat cycle around 6-10 months. If she is this ill I would recommend having her to examined by your vet to make sure she isn't having any complications or other underlying illness that's causing this. If she is found to have a ln abnormally intense heat cycle, then the vet can prescribe some safe pet friendly pain medicaiton for her to get for the next few days until the brunt of her menstrual cycle has passed. In the meantime I try placing a warm compress on her belly for a few minutes (be very careful not to leave on too long or you can easily burn your pets skin) to help ease some of the discomfort. hope she feels better soon!

Being in heat can cause behavioural changes in dogs, as long as they are not too extreme and the dog is otherwise well I would not worry too much. Quite often when in heat dogs well be lethargic and not want to eat very much.