Pregnant, pain during , prenatals, 19 weeks.?

I am nineteen weeks pregnant with a baby boy. When my partner and I had tonight, I got a pain across my lower stomach. We have 1-2 times a day every day, and it just happened tonight. It felt like an ache, the same ache when you run to much or do a lot of sit ups. It subsided when we slowed it down, but it came back. It stopped after . I have felt baby kick and turn since, but what could that have been? Is that normal? Also, I have had such bad morning sickness from 6 weeks til now, and have puked every day since 6 weeks except maybe 8 days. It was so bad, I just stopped taking my prenatal. I haven't taken them the last two maybe three months. I stopped and picked up some Flint stone gummy vitamins, with extra vitamin c. I read that those can substitute for the prenatals? Is this okay? I throw the pills up every time! Thanks so much and God bless!