Im so confused about what my body is doing..

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​My last period started 25th august,

So I got this 3 days of my period being late, why am I getting a Heavy/dull/crampg feeling in my lower abdomen?? Im getting lots of thick CM too, Should I worry?