Advice columnist and relationship expert Matt Whyman answers:
Whether you fancy guys, girls, both, or neither, your sexual identity is just one element of who you are, like the colour of your eyes or your sense of humour. Some people get to grips with their sexuality immediately. Others need time to reach this point, even if it means accepting that gender isn't really an issue for them when it comes to being attracted to someone.
Exploring your emotions
Right now, cancer may well have an impact on the way you lead your life.
"Young adulthood is a critical time for us all, because it's when we strive to find our sexual identity," social worker Simon Darby explains. "Going out with friends, going to parties and meeting new people are ways to experiment. But if you're having cancer treatment that depresses your immune system, perhaps with long spells in hospital, this kind of socialising might not be possible for a while."
Nothing can stop the feelings surrounding your sexuality, but if you're tired, sick and having mood swings from treatment, this can make it harder. What matters is that you're able to make sense of your emotions in a safe environment, and can open up about them to someone you trust without being judged, or made to feel that you have to conform to a sexual stereotype.
Be honest with yourself
Simon says: "Sometimes young people who are lesbian, gay, bisexual, pansexual or transgender are less likely to ask for advice because they worry that a professional might judge them."
Is there someone you feel you can open up to, such as a good friend or family member? Alternatively, if you'd like to talk to someone in confidence and outside the situation, then contact the Lesbian & Gay Switchboard on 020 7837 7324.
You will make sense of your sexuality in time, but only you can decide how to act on it. Just be honest to yourself, rather than feeling this is something you need to justify to others, because you don't.
Think about your priorities
Clinical psychologist Kate Hancock says: "Having cancer does not affect your sexuality, but people often find that experiencing a serious illness like cancer makes them think about who they are, what they want to do in life, and what matters to them. As a result, young people sometimes actually end up feeling clearer about themselves, their priorities and how they wish to live life."
Content added: November 2015
Review due: November 2017