First response 😡

Has anyone else been extremely disappointed in First response test? I’m 5 months postpartum and I got back on metformin to help with my pcos. A week after I started my medicine I had very light pink spotting with a little bit of cramping and I thought my period was about to start but it didn’t and it only lasted that moment when I wiped… anyway I thought it was ovulation spotting. Fast forward to today exactly 14 days after the spotting I took a test (first response) and got a faint line immediately but after leaving the test the line disappeared. I’ve read that this has been happening a lot with first response. I’m so disappointed because I have always relied on them and I thought they were great test. Now not so much ☹️