Period troubles

Eva • Momma to Gracelynn brooks and a little baby in heaven✨ With the man of my dreams for 8 years🖤
Side note* I am normally 2 days late, I haven't had sex in over a month, and I have gotten my period since then. Just not this month yet.* 
I'm on the pill and I am 3 days late. I'm getting frustrated and I can't get my period to start on time anymore and sometimes it really freaks me out. Like I haven't had sex in a long time but I'm normally not this late?¿ My glow calendar says I will start my period tomorrow but I'm almost half way through my "period week" pills. So this isn't working for me anymore. Anyone know why my period is delayed?? 
I was thinking about switching to the Nuva ring? Has anyone had any troubles with it? How accurate and easy is it?