Irregular period but 18days late according to the app

Helen • 27 years old ✨ TTC our rainbow baby ~ Mama to 3 angel babies

So I’m irregular but I’m 18days late. Now the past two weeks I have had period like cramping and my boobs have been a little sore but that’s about it. I still haven’t started so I have no clue what’s going on. I haven’t taken a test because I always feel like it’s just my irregularity and I sometimes do end up starting extremely later than expected or I just don’t end up having one. I don’t know what do you guys think?