late period while on birth control

So I started a new birth control and went on vacation last week. I'm not very good at taking the pills at the same time and I missed a couple during the trip (doubled up the next day). this is supposed to be my period week of the pills and I just don't take the sugar pills so I haven't taken a pill since saturday. I'm at the end of the week and no period. I use two different apps and one says I'm 3 days late while the other says my period isn't until Saturday. I start the next week of bc pills on Monday. should I spend the money and take a test or wait?