I am hoping there is still a chance

Last Wednesday I got a faint positive, that night I felt a stabbing pain on my right side. Friday I took a test and got my bfp. I was so happy. Took a test Saturday it was getting darker. Sunday morning I tested and it didn’t seem to be darker at all. I was dehydrated the day before I have been sick all weekend. Sunday morning my cervix was high and soft hubby and I had sex and now I have period like cramps after and now my cervix is low and firm. This is my 6th pregnancy I have 2 daughters 3 angels (possibly 4). I will call my dr. In the morning but I am really starting to worry. I am not bleeding but I can just see it all falling apart. Any positive vibes would be appreciated.