Hello, I Have Two Queries. First, I Have Had Sensitive

Hello,
I have two queries. First, I have had sensitive nipples for since Sunday. They don't hurt unless they're touched or a heavy shirt is on them. They're slowly getting less sensitive as the week goes on. I thought it was ill fitting bras causing friction so I bought new ones. I've also been gassy and bloated for the last 3 days, I had bad cramps this morning so i thought I would be getting my period but nothing has happened.
I'm on implanon, and I took a pregnancy test this morning, it was negative. I haven't changed anything in my usual routine, I'm a bit stressed at work but I always am. I've been eating a lot more green beans; I don't know if they can cause bloating.
I'm 21, I take a vitamin a twice a day and a collagen boosting table twice a day.
Could it be ibs or something ? Maybe a probiotic would help?
Thanks
Emma