Irregular and Frustrated

I’m really so frustrated with not being able to completely pin point my periods. I’ve been nursing my youngest (2 next week) and I didn’t get a period until August. I’ve had one every month since but it’s about the time we want another baby so I feel like I’m constantly testing for no reason. According to one app, I should’ve started my period three days ago, according to this one I should’ve started my period today and nothing. My discharge isn’t dry which, it’s milky so I want to test to check but at the same time I’m like its gonna be negative and I’m going to get my hopes up for nothing 🙄