7 days late with bad cramps

[shaunax]

HI everyone need some advice and some experience of people this may have happend to,last year I was diagnosed with a eating disorder where my periods had stopped but as I got better they came back slightly and for six months now they have been regular and comes every month (every three weeks)but this month I have sore nipples, urinating alot, 7 days late but for 4 days have experienced the symtoms of starting a period with bad cramps but is easing off and on today, sore back and white discharge without the blood, I am now 21 and healthy, I have been with my partner for four years and we do have unprotected sex and I don't take any birth control but was just looking for advice and what could be happening is it from where my periods was so irregular last year or could it be possible to be something else, thanks x