My 7 month old has high temp a stomach ache is eating less and hardly drinking, he is teething aswell and won't sleep what do I do?

Take him in for exam. He may be having his first exposure to a virus. If so, the biggest concern is keeping him hydrated. It is a pretty miserable experience but it is self limiting. This is very common and if it is the case, subsequent events will be much less severe but may include cold sores. A topical medicine may be prescribed which will keep him a bit more comfortable.
Palliative care. Give your child palliative care: 1. Encourage fluids 2. A children's pain reliever per age and weight. 3. Try teething rings or a frozen wash cloth to chew on. 4. If you child's temperature is not relieved by children's tylenol (acetaminophen) or Motrin and persists for 3 days contact your pediatrician.
See MD. It sounds like a digestive system situation. See your md.