Am i straight or bisexual?

I'm 18, and I've been masturbating since I was 12. Back then I didn't know much about sex or my sexuality so I wanked for fun. Then once I cross dressed pretending like a girl, I liked dressing up like a girl and to end it I'd wank. That went on for some time, when I was horny, I'd cross dress and then wanked. When I was around 14, I stopped doing it. It started feeling guilty and stuff. Since then, I hardly cross dress, once or twice a year. Usually, I just sit on the toilet seat and wank whenever I feel horny.

Here's the part I'm worried about, around age of 15-16, I'd fantasize myself a helpless girl fucked by many men. I'm not sure if I fantasized myself as that girl all the time or just a some girl. Then around 17 and now, I find that guilty too and would usually wank to celeb fantasies and having sweaty sex with a girl or femdom etc. But, then for sometime, I thought of fantasizing men, my dick would get hard and I came in just 20 seconds of wanking (usually it takes me minute to climax), my dick won't even ejaculate more than 1 drop when thinking of men. But, when I'm thinking of women, it takes me 15-20 minutes to hit the climax, and then my dick shots a heavy load. When I'm fantasizing men or being a girl I don't cum much, and then feel guilty, but enjoy it while doing it, which lasts hardly a minute. But, when I'm fantasizing having sex with a girl, it's fun doing it (I might get bored if I'm not fantasizing about an actual girl), I ejaculate good enough, take enough time and then no guilt later on.

But, I get turned on by the thought of cross dressing or sucking a dick when I'm alone. When I'm with my friends, even if the thought hits me I feel ridiculous and nothing happens, I don't fantasize or get turned on, the thought goes to trash bin. I'm attracted to girls, have been since I was 8. I want a girlfriend, I don't feel like kissing a guy or going anywhere near a male body, just the thought of sucking dick turns me a little bit on. But, when I think of a girl, I'd kiss her whole body, eat her vagina, bite her boobs and what all will I not do? So, it's just a weird Dilemma. I know this age is confusing and stuff, I don't mind being a Bi, I'd live with a girl and a guy, even marry both :P But, right now, I'm fucking confused. Oh and I even have tasted my pre-cum while I was horny and this girl side was strong on me, it felt weird, it still does but when 'she' is horny I eat it. I tried upside down position while wanking so cum would go in my mouth. I'd hit the climax and when it's falling on me, I feel PATHETIC and DISGUSTING. Even on Omegle, I sometimes act like a cumdumpster. I don't care what others think, I'm fine with being gay or bi. But, I wanna stay straight 'cause I like girls and their boobs and everything they have to offer. Please help me.