I don't think you have anything to worry about hun :) if it doesn't go soft again you can always call your doctor office and talk to them and see if they feel its not normal, but I really think its just because they are super sensitive during pregnancy the little touch will make them super hard ...heck sometimes it doesn't even have to be touch I've heard women leaking or getting hard nipples at the sound of a crying baby or kitten lol
Yea mynipples have been hard before but this time wont fo away and its just the tip i guess i can say the areola or brown part idk if i spelled it right is soft
My nipples are hard 24/7 pregnant or not , it could just be because they are sensitive right now and not everyone leaks colostrum (milk) during pregnancy. If it continues you may want to mention it during your next appointment but I doubt you have anything to worry about :)