Nervous about line progression

Monday 5/9 I found out I am expecting. I tested at night and got a pretty clear positive on a cheap blue dye. Went back to the store and got a $1 test and got a faint positive. I tested again the next day on 5/10 with FMU & got another faint line. Tested with SMU with a FRER & got a pretty confident positive. I tested again yesterday evening with FRER & it’s faint still. Tested again this morning 5/12 with both $1 and FRER & the $1 is still faint and the line has not gotten darker on the FRER. I know I am still super early in my pregnancy because my period was not due until yesterday. I’m just worried that this baby isn’t sticking very well and that’s why I’m not having any line progression. Has anyone else had this & had a healthy pregnancy?