Iron deficiency and periods?

Megan
So I'm trying to figure out what is going on with myself. 
I lack any sex drive and my periods are a couple days early and sometimes a couple days late. I've also been gaining a weight. I'm not pregnant and I don't not have ovarian cysts. (Just had scans) 
Maybe I'm anemic or thyroids?
 Would that cause these types of symptoms? 
I do have stress in my life but I always have.