First Pregnancy and Worried

I am 6w4d pregnant and yesterday I started having some minor cramping  and a small nagging ache in my lower back specifically on the left side. Today, the cramping began to get worse and more frequent, but not unbearable. I also starting spotting lightly. As the day progressed the bleeding has gotten a bit heavier but not much and the cramps are still here. My back is absolutely killing me, I cannot stand much longer than 20 minutes without having to take a seat. As this is my first pregnancy, I am just wondering if this is common or if anyone else has experienced this? I just found out about the pregnancy last week so I haven't found a doctor yet, but I called my local hospital and spoke to someone in l&d and I was told that they don't see anyone before 15 weeks, but she said since it's still so early in the pregnancy cramping and spotting are common due to implantation. Miscarriage is also common this early in pregnancy but she said as long as the bleeding isn't heavy or bright and the cramps don't get unbearable then I should be fine. I could love to hear anyone else's opinion on this.