It's okay to just do what you feel comfortable with! With religious beliefs, it can be pretty confusing to feel attracted to the same gender. Usually, if we repress those feelings by forcing ourselves to only date the opposite gender it can feel restricting and uncomfortable - and if it makes you feel this way you might want to consider talking about it with someone you trust to figure out those feelings. However, if you feel comfortable doing that, then do what makes you happy!
If you are attracted to more than one gender, even if you prefer one in some contexts or in general, you are bisexual. It may be hard to accept if they have taught you that it's wrong. But ask yourself: is it really wrong, or is it just a cultural prejudice? How can love the love or attraction be wrong, whoever it is directed to? The feelings are the same and just as beautiful, and it doesn't hurt anyone, so how can it be sinful? Love is holy, and sexual attraction is a gift too. The real sin is judging. You can try to familiarize with these ideas and reflect on them, and maybe get in contact with the bi community, to start internalizing the belief that it's ok to be who you are. And you can still believe in your religion and be a good faithful by living up to religion's core beliefs.
You really know yourself best so you're really the only one to be able to say what you identify as. If you feel like you are bisexual, but only don't like the label/idea of it because of religious beliefs, then I think that's something you're going to have to reason with yourself. You'll have to think about what your faith is really about and if you're going to be okay with having the feelings that you do. There are plenty of lgbtq+ people who are religious as well, and they have each found their own ways to come to terms with their faith and identity. Really, you just have to do what you think is best for yourself. If that's accepting your feelings but not acting on them, only on the ones for the opposite sex, then that's fine (as long as it's not hurting you). If what's best for you is embracing your identity (whether it be bisexual or otherwise) and still holding your religious beliefs, then that's great too!
Related Questions: I feel somewhat attracted to my same gender, but only want to date the opposite and would rather go all the way with them. I don't want to be bisexual because of religious beliefs. What do I do?