Could I be?

We are trying for our second baby. We have a beautiful 1 1/2 yr old daughter. We don't want our children very far apart ( I have a sister 8 years older and one 12 years younger and I hated feeling like an only child) and my husband will be 30 in March. Anyway a couple days ago I noticed that randomly bit especially when my daughter would cry my nipples would immediately get hard like they did when I was pregnant/breastfeeding my daughter. My breasts are some what sore and do remember having some cramping. My periods are abnormal . I normally have one every month but they vary on the day and how long they last. My period stopped Oct 30/31 I took 2 tests both negative. I am on metformin which had helped me lose some weight which I know definitely helped me get pregnant with my daughter. Do you think I could be pregnant?