Questions for the ladies off b.c.(???)

Has anyone else who stopped birth control in the past months and started taking pre natal instead start noticing their pants getting tighter. No I'm not pregnant yet but I swear these vitamins are the cause. I eat right I consume no sugar and I eat tons if veggies and protein. I exercise 6 days a week. I've been on b.c. since 16 I'm now 27. My boobs were smaller than an a cup now I'm spilling out of an a up top of the bra. My boobs are filling in. All these changes and I'm not even pregnant yet. The bloating is the worse. Any girls out there can relate???