How can I figure out my sexuality even with all of this doubt and uncertainty?

That's incredible pressure to place upon yourself, and it's going to vary greatly depending upon your experience and whether you are questioning your gender identity, sexuality, or any combination therein. Much of sexuality falls on a spectrum, so that's important to know while you try to uncover where and how you identify. Working with a therapist well versed in both can certainly aid in the process of learning about your unique identity and how you wish to express yourself with the people in your life. 

Given that the end result is likely going to shape so much of your life, one year is a fair amount of time to be exploring, and I would encourage you to remove the expectation that one year would suffice. Many people are still questioning and learning into their middle adult life, and I don't practice with any expectations that there's a finite beginning nor end to the process.

Doubt and uncertainty are both wise feelings, and if you remove the emotions attached to the experience, and you just allow yourself to feel safe knowing that you are your own expert on your life, you can see that your identity is not meant to be concise nor simplified.

There are many advantages to giving yourself freedom to explore and consider your own needs and desires and allow yourself to uncover your own identity with a degree of selfishness and ego centrism.

It's my experience that therapists are generally very honored to work with clients in identity development, and any therapist would be honored to collaborate with such a great client who is invested in the process of treatment and processing their own life in such a grand scale. 

There is a lot of research and resources online to digest and aid with education and comprehension as you go through the process. I'm a big fan of encouraging clients to self educate as this will aid in later self advocacy and aligning with other people with similar situations and identities. Support groups and other resources can be helpful in the process and in establishing affirming supports when life can feel so isolating.