In a long distance relationship but having crushes on friends

I'm in college, in a long-term, long-distance committed relationship w/a guy I love & we're planning a life together. Every once on awhile since we've been LD I find myself feeling awkward around particular friends, like friendly interactions w/the person feels like flirting or like a grade school crush. One week it'll be 1 person & a few weeks later it fades away it'll be someone else (all are people I'm good friends with & never thought of that way before). I feel like it's partly cause I've been missing my bf & attention from someone who cares about me, and partly cause I'm anxious about taking this huge step w/him in the near future & maybe I'm subconsciously freaking out even though i know it's what i want & we're being open & honest about what our wants, responsibilities, expectations, etc. The problem is I know all this & I'm tryna be honest w/myself & w/my bf (i.e. if I realize I have serious feelings for someone else &/or no longer him, I'll tell him cause I don't wanna hurt him) but currently I feel this sorta crush on this guy we'll call Jack. I don't find Jack attractive, I don't think he'd make a good partner, but I've been trying to limit interactions with him cause every interaction feels flirty & making eye contact makes me feel nervous & blush. I don't know what to do. I love my bf so much & I don't wanna hurt him & I already feel ashamed even though I haven't done anything, & don't plan to.