How Can You Tell If You Are Pregnant While Breastfeeding?

I know that you can get prenant while breastfeeding, and I also know that you can get pregnant before your first period. What are some of the signs that you will have that lets you know you need to take a pg test?

How Can I Tell If Breastfeeding Is Stopping Me Getting Pregnant?

Is there tests that can be done or signs?
Answers of ‘stop breastfeeding’ not welcome!
Thankyou.