An endometrial thickness of 11.2 mm just before your period is a normal finding, not a cause for concern. The lining is naturally at its thickest in the days right before bleeding starts, so this fits with where you are in your cycle.
Next Steps
If your period arrives on time with a normal flow, nothing further is needed right now. If you notice unusually heavy bleeding, spotting between periods, or delayed periods again, please see a gynaecologist for a recheck.