Am I paranoid or should I be concerned?

This is my second pregnancy but I don't recall feeling this way with my first. I had an ultrasound at 7 weeks (though I thought I was 8) and the heartbeat was 160 bpm so it seemed like everything was okay. Ever since I've just been feeling a bit off. A few days ago I had diarrhea and I just felt so unwell. The last couple of days I have been having sharp cramping in my uterus and today I'm having very painful abdominal pain. It goes away after a while if I rest but I don't have to do much for the pain to start up again. I'm also a bit concerned that this is my 2nd pregnancy and I'm not even bloated. I started showing around 12 weeks with my first and I'm currently 8 weeks and was sure it would have started by now. Has anyone dealt with any of this? I'm becoming a little concerned.