Cramping like mad and faint lines

Sammy
Hi All. Just a wee bit of advice please. I was due my period yesterday and late and my top test came positive. I did that yesterday evening. Then the middle one this morning and the bottom one now. 
I'm pretty sure there are lines in all of them but shouldn't they be getting darker? Instead they are taking a while to show up. Plus I've been cramping all day and feel so bloated. I have back pain and just generally feel crap. 
Am I having a chemical? Is it normal to have such bad cramps.