hi y'all

My cycle is normal 28 days. My husband and I are ttc. My most fertile days were the 9th-15th. We had sex every other day. About a week ago i started cramping and my breast became very sore. (to the point i couldn't wear a bra) Along with that my vision changed. I just went to the eye doctor late july, so I'm confused on why they changed so much in two months. This morning i woke up and had brown spotting after going to the bathroom. It came and went all day, not enough to use a pad or tampon. I was just wondering if this could be implantation bleeding? My period is not due until the 31st. Any ideas on whats going on with my body?

Here are somethings I'm feeling:
1)Cramping
2)Sore breast
3)Fatigue
4)Vomiting
5)Now Spotting

ANY input would be greatly appreciated :-)