there. Thanks question. Let me see if I can help.
If your dog seems feverish or is unwilling to eat, you need to get her to a vet soon.
Could she have eaten something she shouldnt have? If so, she may be constipated and painful because the foreign body is stuck in the GI tract. Socks, trash items, dog toys are all common causes. If your dog chews on bones, this could also get stuck in the GI tract. if you think a foreign body is a possibility, you need to get to a vet ASAP.
Otherwise, to help with constipation...
Make sure the dog is well hydrated. If you feed dry dog food, wet is down well before feeding or switch to or add in some canned dog food. You can also add some canned pumpkin (not pie filling). Add a tablespoon to each feeding.
Give that a try and see how things go. If you continue to have trouble, then I recommend seeing a veterinarian. Good luck