Help me please I don't know what to think

About a week and a half ago my nipples started to hurt now all of my breast is sore and I'm having cramping like feelings in my lower abdomen area and this never happens befor I start my period. I took a hpt and got a faint line latter that night I went and got a cheap 1.00 one and it said no. I'm not due for another 4 days. I took a 1.00 test this morning and I thought it was a BFN but I came home from work and re-looked at it and I saw a faint line and so did my S.O..

could it just came up because it sat all day or could I really be pregnant