Is your fear based on your actual experience visiting the US so far, or is it coming from somewhere else?
I’ve had over 12 visits before I moved to the US, more than half of them were while I had an immigrant visa pending.
This level of anxiety is not healthy. Maybe you are young, maybe you are an anxious person, but try to calm down. Continue to build strong ties to your home country, continue your relationship with your boyfriend and just keep going strong.