I am depressed, i need help with my uality, i'm so confused? (long but I need help)?

Well i'm 16 years old and I don't know if I am straight, , bi-curious, gay, panual, aual or heteroflexible. I don't know what to do with my life, i keep going back and forth. I've had girlfriends in my time, and have gotten successful arousals and s from them, i lost my virginity to one, and i have only done ual stuff with girls, never guys. I also love having a girlfriend but i dont know what it is, i feel like i am always being tested BY ME, to see if i am straight gay or . If i'm with a girl i feel like i have to have with her, like its a necessity or else im gay, yes i know it sounds stupid but idk why that is! I feel like i can't get an with a girl so i have to 'prove' it that i can? I feel like the cause of that is because I would lose my with the girl i lost my virginity to but idk if it was because of nerves etc. I remember one instance when one of my sisters friends came into my room and i had an incredible urge to have with her, but she teased me haha, and i didnt end up having with her. I have gotten involved with a dude, but it was a long distance, and i got incredibly infatuated, but now im like "wtf, what was i thinking" because i have no urge what so ever to have with him. To be honest i dont ever have an urge to have or do ual stuff with another guy but some nude guys turn me on a lot, even more than nude girls! And it confuses me so much, for example yesterday night I wanted to test myself, and i looked at a nude women and a nude man, i felt some type of sensation while looking at a guy but not very significant and nothing with a nude girl until i started thinking about doing stuff with that girl, then i got turned on by her. I find myself ALWAYS feeling depressed when i masturbate to , especially gay (which I dont do very often anymore, but i DID in the past which makes me feel depressed and dirty). I want to be with girls i like them a lot, but i feel like some ual sensation lingers with guys, and i dont want that to chase me for the rest of my life. Sometimes im only attracted to women, sometimes only to guys, and sometimes both. that is what confuses me to the point where I start thinking super irrational. Please give me any advice.