Help me

So I haven’t had a normal period in over 3 years due to depo. 4 months ago I switched to the non hormonal copper iud and had what I thought was my first regular period which ended about a week ago. So I don’t remember much about periods :/ but I had some white discharge 3 days ago and then it’s been brown since. Why?? I’m not sure how periods work anymore. Me and my boyfriend have unprotected sex but I’m like 85% sure one of us is infertile due to trying before and never conceiving.