There is nowhere in scripture that explicitly condemns it. That being said, to lust inappropriately in your heart (mind) after someone is sinful and seen as the same as actually committing the act itself. So, that being said, I PERSONALLY (I do not have a verse that explicitly backs this up, but it is where I come down) believe that if a husband and/or wife are unable to have sex for health reasons, or they are apart for extended periods of time, or some other circulstance, I do not see it as sinful to masterbate so long as they have in their mind their husband/wife. Ideally though, husband and wife should be intimate together as much as they can.

If it were me in your shoes (and I'm not in your shoes, so take this for what it's worth) given your current state of uncertainty regarding your sexuality, and the fact that you arent married, I would encourage you not to masturbate and spend lots of time in prayer and reading scripture to help you in your predicament.

I speak as a fallen man who sinned in this area A LOT in the past so I do understand some of your pain and frustration. I pray that the Lord would be with you, strengthen you and that he gives you clarity, and a spouse one day so that you both can have a wonderfully fulfilling sex life.