[Megumikai]

I've taken a number of tests and from those and reading descriptions I've narrowed it down to these three. Is there any way to narrow it down further? I'm very interested in finding out my type but the continuing tests and searching the internet has given me a headache so I thought I'd post some here. Any suggestions for what I should do?

 

[Vaka]

I don't know if you've tried looking at cognitive functions, but both ISFPs and INFPs have the same dominant cognitive function...'Introverted feeling'.
I think that IFPs have a kind of desire to understand people and their feelings and perspectives that lends to strong empathy. They want to understand peoples' motivations before making a judgment as to whether they are immoral or moral. That's kinda basic, but if you can relate to that closely, it would atleast rule out INTP.

 

[vel]

You can google up the cognitive functions of the types, especially dominant and auxiliary ones, and then read over the descriptions and see what you can relate to the most:
INSPs - introverted feeling dominant, extraverted sensing auxiliary
INFPs - introverted feeing dominant, extraverted intuition auxiliary
INTPs - introverted thinking dominant, extraverted intuition auxiliary
Also visit forums of these MBTI types and read over the sticky threads. There are usually threads like "you know you are such-and-such type when" where people post characteristics that they thing are specific to their type. After reading through these threads you may find that you relate more to one but not others.