Help!! HPT aholic! Second test today was lighter than the first

My husband and I have been trying to 2 years and I finally got my bfp on Wednesday - it was light but got darker and darker every morning I took a test- today I didn't have the good brand and had to use a cheapy shop rite brand and the test came back super light again. I also didn't use the first pee of the day but it was still there. I took a second one this afternoon and it was lighter than this morning - should I be concerned or is it just the difference in brand and timing? I know I'm being neurotic it's just been a bumpy road