You can't test after just a few days. It takes at least 7-14 days for implantation to occur, and normally after two weeks is when a test can be accurately used. 4 days isn't enough time. I doubt that the bleeding was due to implantation or anything as well, since 3 days doesn't give enough time. It could have been due to ovulation or just random spotting. It's impossible to say if you are or are not pregnant. You'll need to wait another week or two and retest with first morning urine.
There is a chance... Probably too early I got my bfp wen 4 days late... Clear blue