What's the difference between having a heterosexual person having sexual attraction to someone of the same sex or a homosexual/bisexual/pansexual person having sexual attraction towards the same sex?

Feeling depressed by the thought of falling in love with someone from the opposite sex does equate with not feeling any attraction for someone from the opposite sex?

Is it normal to feel condemned when thinking about having a relationship with the opposite sex?

Just in case you're thinking about replying without answering specifically those questions... No, I haven't been sexually abused by the members of the opposite sex or had bad relationships with them. I ended up by having some bad opinions about them(possibly because of how I was taught) and I'm wondering if I am straight/bisexual, but in denial or if I am really into girls. I may not get the answer right away, but who knows if someone gives me a hint to how figure things out.