questioning teen

I'm a 16 year old female and for the longest time I've been in relationships with guys. It's a been a while since I've been in any relationship however. I've started questioning who I am. I like females in a emotional and personal way. I've always been closer to them. Although I've had a relationship with guys, I could never be intimate with them (I have never kissed anyone). Also, when friends show me pictures of shirtless guys, I don't react to them the way they do. And with girls, I could sit on their lap, cuddle, etc. but could never do that with a guy. I've never thought about girls in a romantic way but I can see myself being with one. I'm terrified that I think that and I just want some guidance. I've had depressed spells and loss of sleep over this. Any response will help. Thanks