Plan B and IUD

So I’m dumb and let my boyfriend use withdrawal method.. twice. That’s not the only reason I hate myself at the moment. I also have an appointment to get an IUD implaced tomorrow. I was so close but I let hormones get the best of me. Anyway He pulled out and had to rub himself immediately after to make himself cum so I know he didn’t ejaculate in me but I’m afraid he might have pre-ejaculated and I know there’s chance of live sperm in that. I’m scared that if I take a plan B pill and get my IUD tomorrow that it will have bad effects. Maybe it won’t and I’m just dumb but I could use some advice on what to do. I don’t want to tell my doctor tomorrow cause I’m afraid if I do that she’ll delay the IUD in the chance of me being pregnant and I’ve been waiting for this appointment for months. Any advice please?