Hello ma'am and welcome.
Lemon and warm water is very healthy for the heart and to help control cholesterol
levels if taken after each meal, and I know many women who take it on a regular basis on and off their period.
I doubt this can cause a delay in your periods, and so there should be some other underlying cause for such a presentation. So speak to your doctor about this, and if at all you need help then your doctor will prescribed you medications to have a withdrawal bleed.