Hi Tamara,
I ease tentatively into the "role" of "commenter on other people's charts" on this site because a) I'm not an astrologer and b) humans are very complex, and I don't really know you. But then, I post things on this site because I want to hear what others have to say about it, so I want to give back in the same fashion. Take my post for what it's worth...
So again, the human psyche is profoundly complex. Complex enough that its quite normal for us to be a mass of walking contradictions. That great pioneer of modern psychology Sigmund Freud saw us all, essentially, as internally, and mostly unconsciously, conflicted - caught between the grand drives of love and aggression. We can all, and often do, love and hate the same thing at the same time. The same person at the same time. Granted a vast number of us walk the world rarely ascending beyond the realm of sheer instinct. But for those who want to be more consciously aware of who we are, what we do and why we do it (and I always assume whenever anybody is digging into their own chart that's exactly what they're after) life becomes a eternal process (struggle?) of navigating our own inner complexities and conflicts in a way that allows us to find the best in ourselves.
So if you feel a contradiction between aspects of your inner self, or maybe your inner self and the "roles" you play in wider society, I'm with greybeard in suggesting maybe the task isn't to "fix" what Nature made of you - where by "fix" we mean do away with these traits of "sensitivity" and "being a loner." (Traits, by the way, which sound fantastic and highly desirable to my ear!)
On the other hand, I'm with you if by "fix" you mean simply "get a better handle on." if you mean that you've identify some issues with yourself that you're looking to better understand. if you mean you have some traits that feel right now like vices but you want to figure out how to turn them into virtues.
My first thought is that being profoundly sensitive and a loner aren't contradictory at all, and I suspect they are both expressions of the watery side of your character (particularly, maybe, your Pisces Sun - though I could see a Saturn/Neptune conj. (in Cap!) expressing the need for spiritual rejuvenation through periodic hermiting). I suspect your need to be an occasional (frequent?) loner has everything to do with your body's need to re-charge after constantly sucking in and dealing with everybody else's psychic stuff (your sensitivity).
Second, again: I'd see your innate sensitivity as something that can be a profoundly good thing. What a gift to yourself and others. If you learn how to manage it so that it doesn't overburden you with the weal and woes of others (not that I'm a master at that myself. Pot calling the kettle black...). Again, I think your "loner" instinct is your body's natural mechanism to ensure against overload. The answer might lie in some conscious awareness and acceptance of the need to get away and meditate in a frequent and routine fashion ???
Finally: again, we're all a mass of contradictions. Just from watching people in life you can see that nobody is simply one note - but looking at astrology charts has really confirmed that for me. Again, I'm no astrologer. But when you say that you're actually "dynamic in my decision making" I see your four key angles (ASc, Des., IC and MC) in cardinal signs and I think "yeah! That's right you are!" In this life you have a cardinal persona: driven, creative, pioneering.Cancer, note, is the cardinal water sign. I often find when people emphasis the sensitive, mothering nature of Cancer they miss a lot of that sign's complexity. Or they miss a lot of the complexity that goes into the "mother" archetype. Cancer can be fierce. Relentlessly pushy in indirect ways. Profoundly good at getting what it wants through passive-aggressiveness. Or just straight aggressive when cornered or threatened. A Mother Bear ripping you apart to protect her cubs. It is the sign most associated with the need for psychic security after all. (Isn't it? Astrologers?)
I also think that Sagittarius moon probably throws some interesting spin into the "watery" chart mix. In the part of your psyche that we most associate with water - the deep, inner psyche - the Moon - you're actually not water. You're fire! And unstable, mutable fire at that. Which suggests to me that your outer expressions, your social role, are typically watery sensitive - Sun and Ascendent in water signs - but your inner, unconscious self, is energetic, vibrant, prefers freedom from such emotional entanglements and feels secure when you are moving about and expressing yourself.
That's my to cents, anyway. In "fixing" these traits you currently experience as difficulties, I'd suggest the task isn't to figure out how to cleanse yourself of them but to consciously master the inner complexities and conflicts, and figure out how to balance them - bring them to work together somehow - so you can find the best expression of that really interesting chart - that really interesting mix of water and fire - that you can.