In all probability, your doctor when he told that 'your blood is getting thin' meant that there's reduced number of red blood cells (rbcs) along with reduced level of hemoglobin in each red blood cell.
Now the function of rbcs is to transport oxygen to working cells. Oxygen attaches to hemoglobin in the rbc and thus carried to the cells.
So, in effect you suffer from anemia.
Effects would be low energy.
Next Steps
You need to make improvements in your nutrition to get enough iron, folate and others; this will help your hemoglobin and rbcs to rise.
Health Tips
I can help you design a nutrition plan to help overcome this. Please book a consultation with me and we can talk about this in depth.
thanks,
Dr. Deepak