could I still be pregnant?

I usually get my period like clockwork especially with glow they predict my periods so well and have done for a while now, I did miss my period by 5 days and on day 6 she arrived, I'm almost desperate to get pregnant but last month we just gave up almost completely with the odd few days of passionate sex. my issue is that I got 2 BFNs last week. my period is usually 6 days long and never more never less, all of a sudden day 4 it stops. doesn't come back. so I was thinking even though I had my period could I still be pregnant? it was very light at watery and just abnormal. I have 2 tests in the cupboard but I'm scared to waste them. I seriously want a baby and so does my partner. how tf do people get pregnant by accident? they're so lucky it's unfair. I won't be replying to comments except on here as I want to be anonymous, also will separate replies to comments with gifs because pressing enter doesn't create spaces which is annoying asf!