No symptoms

So I am 7 weeks and have my first ultrasound on Monday (5/15). I have had no symptoms throughout the last few weeks other than some cramping here and there during week 4/5. In week 6 and this week I really don't feel anything I haven't had any sickness, nothing.
I'm a worrier naturally and just feel like something is wrong. My biggest fear is going to the dr and there being no heartbeat. Has anyone had no symptoms thus far and everything been ok? I'm really trying to stay positive and happy.