Struggling with me gender?

Hadley • 18. Engaged. TTC.
About a month ago I came out as gender fluid. I've always known I was bisexual but sometimes I feel like I'm just more of a boy?
Lately I've been struggling internally with my gender. I feel like I may be transgender female to male. I'm engaged and have been with my fiancé for going on 4 years. When I mentioned it to him he said its "Hard enough dealing with me thinking I'm gender fluid. 
What do I do? Who can I talk to? How do I find myself...?