Worried :(

My period is a few days late but I’m not cramping at all. I haven’t been spotting or anything either. I don’t know what it is and I did have sex after my last period but I’m taking my birth control pills everyday. I’m sorry if this is dumb but I’m worried. I’m also scared of buying a pregnancy test because my dad would kick me out if he even knew I took a test. Thank you for any help, I appreciate it.