Left a pregnancy test in the bin and...

Tally

Hi there - I am new to this. I came off the pill in early Dec, had a period starting 27th Dec, we gave it a go - and my period is a few days late. I did a test on Friday, it was negative - then did a test yesterday morning, it was negative and then I put it in the bin. I have really bad lower back ache, my sense of smell is heightened, hip aches, and I thought I must be getting my period. My friend suggested the best early brand of pregnancy test and I went to the bin and pulled it out to check which brand I had used. I looked and now I can see a second line. I am quite shocked, and unsure. Maybe it’s a mistake? I obviously don’t want to get too excited but any advice would be amazing. Thank you xx