When you got pregnant while breastfeeding did your milk slow/stop?

My boy is not my first or even my fourth in the line up lol. All my babies have been breastfed with a problem. But now I’m ttc and breastfeeding and lately he’s been fussy about breastfeeding and I’ve been having problems getting him to latch. He’s 7 months old. Could this because I’m pregnant? I test in a few days.