How do I deal with having a Fire Sun and Water Moon sign together?

I'd like to suggest you to be fully expressive of your personality and not try to suppress any part of it. I think Astrology works its way into our psyches in strange, almost harmful ways because it makes us too aware of our shortcomings and specific traits, which may or may not have been actual problems for us to begin with. Things might have been working more seamlessly for you before you delved into Astrology. It's not too late because the stars don't compel you to be a certain way in life. You can reach the pinnacle of your best self and not give two hoots about what your natal chart says. Being complex and contradictory is not a burden, it's a blessing.