Just because it’s not something out there being used by others doesn’t mean it isn’t “legit” - this could be a personal symbol of yours, @magan, that holds powerful meaning and symbolism for you as an individual 
If it is a personal symbol/sigil, then it’s meant for you specifically. I would urge you to meditate and focus on the sign, perhaps call on your deities or guides if you have some, and consider placing it on your altar or other sacred space. If it has deeper meaning for you, then I am sure that meaning will reveal itself to you with time.
Again, personal symbols are very personal, but I would point out that the number 3 did jump out very strongly to me. 3 is a powerful number not only in magick, but across religions and spiritualities.
Here are just a few potential associations with the number three:
Perhaps looking into those meanings could be a place to start to learn more about your sigil?
Wishing you all the best with it - blessed be, Magan! 