Started nexplanon last week, had protected sex yesterday, woke up this morning with period like cramps am i pregnant? and is this normal i nexplanon?

Not likely: Nexplanon is an under the skin product that starts working to suppress ovulation as soon as it is placed. So pregnancy is less likely. The cramping could be a side effect of the the implant since this is your first cycle with it and the body needs time to adjust. Tell your doctor about these sensations so s/he can guide you as to what to do next.