Help!

So on Tuesday I took a test and it was positive. Same thing Wednesday. Last night after I peed and wiped I had bright red blood. More than spotting, less than my usual period. I went to patients first and all she did was took a urine sample. Came back positive. She said it was probably implantation bleeding... ive been worried, so I took another test this morning this test came back with a much lighter line than the others. Does this mean anything? I always thought the line should get darker as you progress?