worried about call out

I'm 18 and work part time at a discount retail store and am scheduled tomorrow. I've recently caught a cold and I'm worried after I go to bed and wake up it'll be worse and too bad for work. It's currently 2am, which I know, don't stay up so late before work and if you're sick. My shift doesn't start until 1pm and my sleep schedule is definitely something I need to work on.

I know I can just call out sick but my concern is tomorrow my friend is throwing her birthday party and these past 2 weeks I have been trying to ask coworkers to cover, and mentioned to a mutual friend going to the party I'd be there while my manager was right next to me.

I know this is such a dumb complaint and thing to be worried. And I am definitely overthinking everything. I know I really should just call out if I'm too sick to work tomorrow. But I'm worried they'll think I'm faking just to go to the party instead and risk getting a write up or even fired. Most of my coworkers know I was trying to get tomorrow off and covered.

No one can cover. At my store when we got hired we were assigned a team, floor, registers, or back stock. If you're hired registers you can only ever work registers unless someone quits or gets fired from another team. I'm on registers so I can only ask the other people assigned to this team.

Does anyone know how to go abt this and handle it? I know I am overthinking this but I don't want to lose my job because of any wrong decisions or a call out.