Ovulation or implantation

My last period was 9-18, I am due for my next in about 10 days, for the last week I have experienced faint cramping, backache,  spotting and tender boobs (in 31 years my boobs have never hurt during ovulation or my period). Could this be my body just changing or is this signs of implantation?
Has anyone had any similar experiences? 
Also, we just had a consult with fertility and he had mentioned possible IUI's, does anyone have experience with them & what I should be prepared for? (Sorry so many questions, I really appreciate any help!) thanks ladies!