I know what you mean. I am not used to feeling happy for no apparent reason either. I thought it was some sort of high when I knew that I have no drug in my system. Now that I have an anti-depressant in my system, I have that one other time to compare my experiences to. I still wish I could borrow someone else's brain to know what "normal" happy is like. I'd just keep an eye on things. I suspect you know what to look for. If you don't, just enjoy the good mood and keep an eye on things.