A few pregnancy Normal or not Questions!

Jessica
1.) Im 19w6d (second pregnancy) and my left nipple only is seriously so sensative. Noticed when my husband tried foreplay, it feels like a needle is being pinched through it when bent, idk how else to explain that! Not pushing in, but slide ur hand across ur boob an hit the nipple, thats what i mean. Only on that side does it feel that way! Not my other, is that normal?
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2.) I havent ben feeling the baby much anymore, it was alot now it has subsided! But the heartbeats still there! I have a home doopler! 
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3.) My belly seems to not have grown in the last 2/3 weeks ish! But my weight is increasing, which worries me that number 2 could be an issue?!? 
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4.) sex hurts
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You dont have to answer all but someone give me peace at mind? Esp number 1