As a Pisces, by nature, I lead with my emotions; the only sign that limits logic ONLY as a secondary option of existing. As a person who leads naturally with a "dive-in, heart-first" mentality, I'll say firsthand that this is very dangerous. It is very rare to find a partner who will not ridicule overwhelming emotions. Due to this, it is not fair to yourself or the other person to place the responsibility of your emotions in someone else's hands. It is always necessary to lead with a balance of logic and feeling to avoid over-analyzing with your heart and the cloudiness of not thinking things through.
Recognizing that leading with emotions is dangerous, you have to understand how easy it may be for you to overreact to minimal things. It is not to say that what you are feeling is not validated; you may have a very logical reason behind the why of your emotions. The biggest point to take away from interacting with a heavy heart is that the other person is not obligated to those emotions. If the person cares about you then naturally they will care that they hurt your feelings, however, should not be held responsible for the emotions that you have the inability to keep under control. If you are aware that you are a bit more sensitive about specific topics and concepts in general then it may be best to check those emotions before actually interacting. Take a few moments when you recognize that your feelings are being hurt and truly ask yourself if the person has done anything to warrant how you are feeling. If the answer is yes, then stop and wait to respond. Otherwise, you end up following through with expressing those emotions so they are not as heavy, but may catch the receiver off-guard because they are your emotions.
Building thicker skin about the things that hurt your feelings is one of the greatest defenses to overreacting.
Being hurt enough, I had to change my approach to strengthen my logic; I encourage you "feelers" to do the same. My joy comes from giving, therefore, I've learned that I am blessed in the end, regardless of how I am treated or taken for granted for how deeply I care. Keep in mind, everyone reaps what they sow, more than they sow, later than they sow; so your giving heart is always winning for you behind the scenes, whether you know it or not.