Lost 10lbs in less than 2 weeks and a little concerned

I decided to start to lose weight. starting weight was 162 lbs im 5'1. its only been 1 week and 4 days and weighed myself this morning and was schocked the sacle said 152lbs. Im actually a little concerned though cause although im happy it just seems way too fast. All ive done is cut my portions no working out.