You sound like me with my cycle and wanting to get pregnant. Yes your body can make you feel pregnant if you are stressing over it. Your cycle days are in line with mine and almost exact length only mine are 28 days like clock work. I was told by my doctor that if I am feeling pain sometimes it can be related to bowel and more so if it is left side. I found that if I eat or take in a fair amount of fiber a day then things flow better and that left side pain is not there. On another note when it is right side pains for me it is all ovulation and it is so bad the best way to describe it to my dh is to say someone has grabbed his package and squeezes as hard as they can. now you know what I feel. That is my ovulation pain. anything else was or is just cramps and if and when I can remember when I was pregnant it was pain lower and only on the sides like ligament pain or position. That is the pregnancy difference. yes it has to stretch and grow so it hurts, but more in the early first two months when it is bad.