Hypothyroidism vs PCOS

How can you tel if you have one or the other? They share a lot of similar symptoms and I feel like it would be difficult to tell? What tests would be done for both?
I'm experiencing a lot of the symptoms and trying to determine if I could have one of these issues. I have a decreased libido, thinning hair, more acne, irregular periods(I've missed two in a row), am irritable, have some random long hairs I've noticed on my face, always tired. I'm starting to worry because i don't have insurance...what are the side effects of either of these goes untreated?