Different results from different brand tests.

On September 17 at noon I took a sure aid brand pregnancy test and it came back negative. September 18 at 3 am I took another sure aid test same test as before and it was a bright pink positive September. 18th at 6 am I again took another sure aid test same as the first 2 and it was bright pink positive September 19th at 6 am I took a dollar store test and it was blatantly negative. I'm so confused any insight please I'll post of the first 3