Difference in tests between pregnancies?

Caitlin

Has anyone noticed a difference in darkness of pregnancy tests between pregnancies? I just got a BFP and we’ve been TTC for 4 months - I’m cautiously excited! The problem is with my son, my tests were very obviously pregnant at 12 DPO. Today I’m 12 DPO and it’s faint - more like my tests at 10 DPO with my first pregnancy - and not darker than yesterday’s 11 DPO test. I’m now panicked about a chemical. Any thoughts?