Nervous about ultrasound

I have my first ultrasound this week (pelvic ultrasound). I am around 7 weeks. However I was spotting last week (just twice in one day and nothing since then) but I am TERRIFIED that they won't find a heartbeat on Thursday. I just can't help but be scared that something is wrong. I just don't feel pregnant other than feeling like a whale who can't get comfortable in the bed (which is ridiculous this early on...haha). Anyone else experienced the same thing?