It is possible for me to like girls one day and guys the next, but rarely at the same time?

Hello! Welcome to bisexuality or pansexuality (these terms differ and you can choose the label you are comfortable with). As someone who is bi, here's what I feel about it. I've dated more men and I've only been attracted to one woman I know in my real life. And that will never erase the fact that I'm bi. There's no proper way to define how you are attracted and maybe there's a particular trait that you're attracted to, maybe you have a type. None of that will undermine how you feel about a person. The best you can do is stay true to yourself and not compare your attraction to people in socially acceptable norms. However you feel is valid.

Yes! Bisexuality is a valid and very real thing. There are no rules for who you like when. Also, remember that you will like who you like based on factors other than their gender. You can be attracted to anyone that catches your eye. All of that is a strong indicator that you are attracted to the soul and essence of the person rather than their gender. Don’t listen to anyone who tries to tell you it is a phase. And finally, anything is possible. Your sexual preference will change over time in terms of what you find attractive about people, but this is not a phase you have to change.

This feeling is totally normal. If you want to put a label on this feeling you could be bisexual or pansexual among others, but it's okay to not label it as well. Either way, some people have a preference for the gender of their partners, but others don't. It sounds like you don't have a strong preference and its causing confusion when you feel attracted to different people. Try to be patient with yourself and understand why you're feeling this way. Remember that your feelings are valid and as long as you're not hurting anyone you are allowed to like whoever you want.