Bleeding when being on BC? Is it normal?

I have just started using Ortho Evra patch. This week I have been using my second patch, and 2 days ago I started spotting. I know it is written in the brochure that spotting is one of side effects, but I don't know whether it is normal and I should keep using BC, or I should quit. I am getting nervous. I am having an appointment with the doctor on Tuesday but I have got to change the patch today, so I don't know what to do. Change it to the last one in the pack or forget about it. Can anybody help me, please? I am new to things like that, and I really need help. Thank you.