I have had diarrhea for a week and i think i have developed dehydration how do i treat it at home and not go to the hospital? is it severe?

If you are well: enough to be on the internet, it doesn't sound like a trip to the hospital is necessary. You may have some mild dehydration. The trick is to not overdo it. Small amounts of fluids frequently are needed to rehydrate yourself. Try to avoid sugary drinks and fruit juices. They have a laxative effect. Gatorade, sports drinks are good. If this persists, or becomes bloody, fever...then see a doc.