first time ttc

So me and my s/o are ttc and my doctor gave me prenatal vitamins. I have been taking them for 3 weeks and starting last week my nipples started to hurt. occasionally they would feel heavy, but today I feel like they are heaver and they hurt. I know I'm not pregnant because I've been off the pill for 2 months and my doctor said that my uterus needs time to get back to normal. so my question is: Is it normal to feel this way while taking prenatals or is it just me ? also is it just me that prenatals make my sex drive go crazy?