I'm scared!! Slightly TMI

Kim
This is my first pregnancy, I found out on Monday. According to Glow I'm 4W6D today. 
Since Monday I had lite cramping on my right side only. Then suddenly yesterday afternoon I had 1 period type cramp and then nothing. When I woke up this morning I had another period type cramp. I also noticed this morning I had some light brown spotting, hardly noticeable. 
Could the cramps I had earlier have been implantation and now I have the spotting? Is this normal? Or is this the start of a miscarriage? 
I don't have an appointment with the OB till 10/22. I'm just really scared.