Frannie, from the way that you've described this to me, it sounds like you are currently in the process of actually finding "the real you". For some of us, our dominant personality traits appear and become dominant at a relatively early age. For many others, it takes much longer for our personality to settle into what it considers normal. Also, depending on the situation and the stimuli (aka what you are doing at the time), your personality could shift or change to act as a defensive mechanism. If you have to talk to a guy that you really like, your personality could change from being shy and introspective to being totally outgoing and extroverted.

The thing that you need to remember is that we are all "works in progress" for nearly all of our lives. Our experiences shape us and help to adjust our thoughts and personalities into sometimes new and different things. While these shifts could be confusing at times, they are a natural aspect of the human condition.

It sounds to me like you are just going through another stage of becoming the person that you will be in the future. If these personality changes become very manic in nature or your emotional state starts to shift radically or quickly, then I'd advise you to see a specialist to give you a more personal evaluation. But, from what you've said here, it sounds like you're just like all of us. It might take a little while to really settle into what your personality will be, but I think that you are already taking the first couple of steps in the right direction.