Dollar tree test questions

I usually vary in which test I buy month by month. This month I was low on cash so I stocked up on dollar tree tests and 88cent tests from Walmart. I normally have 33-34 day cycle. I finished my 4th round of femera with trigger shot this round. Had severe breast pain and lots of cramps/pulling/pressure in my pelvic area that did not feel like period cramps. I was told by my ob this week that the breast pain was more than likely from the shot since it is a side effect. I tested last Thursday and Saturday -both were bfn's. This morning (day 33 of my cycle) and I thought it was a bfn. Now I know that you are not supposed to go back and check your tests because it could be invalid. I have always double checked my tests and I have never seen anything- not even an evap line where the test line should be. This mornings test: something told me to go back and look at it and I see some sort of line. I even compared the test to the one I took Saturday and it looks totally different, even in the color of the white on the test (today's is more yellow, Tuesday's is white). I had my husband look too and he even saw the line. I don't want to get my hopes up, so I'm trying not to get my hopes up. Has anyone else ever seen a line after taking one of these?