I have had sharp pains in my left breast, stomach aches and have just end a 17 day long period. what could be wrong?

See below: Problems like these can only be correctly handled by your doctor in person. He/she needs to listen to you, perform an examination and possibly run labs or other tests. That's the only way he/she can find out what's going on and what to do about it.

Dehyration?: Having a long period causes you to be anemic and also lose some water. I would think it is unlikely your electrolytes are off but you can see yuor doctor and ask.

I think I answered : You could be dehydrated, anemic or maybe your electrolytes are imbalanced. Need some simple blood tests to find out.