Swallowed 10ml of mouthwash should i be worried? is 10ml considered a small amount?

That's 2 teaspoonsful which is considerable. Did the bottle have instructions on what to do if mouthwash is swallowed? If not call the poison center for advice.

Mouthwash contains fluoride and others some form of alcohol. A small amount if swallowed can cause some gastric distress. You could feel queasy or some nausea, but this should go away soon. A large amount if swallowed can cause dizziness or some drowsiness. If more serious symptoms occur call doctor or 911 ask for poison control center.