So, there are a few things that jumped out at me in your question. The first is that many people assume that, in order to be bi, you have to experience and equal amount of attraction to all genders. But from what we know of how people's attraction works in the real world, it's actually very rare for someone who's bi to experience the exact same amount of attraction to each gender, or for that attraction to feel the same way every time. You can find a really great explanation of why that is here: https://www.scarleteen.com/article/advi ... _and_women
Another thing that may be going on is that it sounds like your experiences kissing men have been with guys you felt pretty "meh" about. Your brain is in many ways your biggest sexual organ, so if it's not into what's happening or who it's happening with, sexual interactions are unlikely to feel great. If you're not really attracted to them someone, then kissing them is unlikely to feel like much. So some of what you're experiencing may be more about the guys you've tried things with, and less about your attraction to men as a group. Too, I'd encourage you to only make out with people who you feel really attracted to going forward (after all, just because someone likes us doesn't mean we need to kiss them). If it helps, we can also talk about ways to find that attention or intimacy you're craving that don't involve being physical in ways you're not really into.
Now, it is entirely possible that as you go through life and learn more about yourself, your understanding of your sexual orientation will change. You mention being scared that you may be a lesbian. Can you tell me a little more about why that's a scary thought?