should I test or is this all in my head??

So I have been having cramps for a wanna say a good week now they are mild . Usually before my period is about to start I get cramps and lower back pain that's how I know my period is coming . My period is irregular sometimes it comes on the day it's suppose too sometimes it'll be a day maybe 2 days early . I have 2 period trackers 1 says it was suppose to come on 11/16 the other says it was suppose to come on 11/18 . I do not know which to go by but either way I'm about 3 days late according to one app which I use for every period . Since yesterday I have been having stomach soreness it ranges from my stomach to my sides . Today I am having the same soreness and I have been having middle back pain usually before my period I get lower back pain never middle . Also I feel as I am sore around my waist which I also never get . I do not exercise so I know that isn't it . I'm I'm holding back from taking a test for a couple more days since my period is so irregular but lately I have not been feeling myself . My body does not feel like normal . Any advice??? Should I take a text or is this just all in my head .