Pregnancy while breastfeeding?

My husband and I had a couple accidents this month. Yes a couple. Ironically we are not trying but ever since my oldest son has been praying for a another baby it doesn't matter what brand, type or size of condoms we use, it's been happening. I am currently nursing my 8 month old and haven't had any periods to track yet. Do any of you breastfeeding moms know when the best time to test is? Especially with scattered incidents? Tests can get pretty pricey on top of all the condom purchases 🤦‍♀️