Since you have started your job and have started experiencing this problem only recently, it is unlikely to be very serious. Numbness of the toes or fingers is usually either because of nerve damage or reduced circulation of blood. In your case, there is no reason to suspect that you have suffered nerve damage. It is however very likely that due to the nature of your job, your blood circulation to your toes is affected through the day, which has eventually started causing the numbness. The first thing you should is change your footwear - it is quite likely that your shoes are too tight for you. They may of course be okay for regular use, which is why you have never found them tight till now. However, the fit might be a bit too tight to be standing in them all day. This is especially so because after having been on your feet for several hours, your feet will tend to swell a bit, causing the fit of your shoes to be a bit tighter. If they are excessively tight, circulation of blood to your toes will be affected, and by the end of the day you will find your toes rather numb.
For the next couple of weeks, try wearing loose, open shoes at work, if it is possible for you to do so. If not, you should at least get a pair of work shoes that are one size bigger than your current pair. This should solve the problem, and you should notice an improvement by the end of the first week itself. Make sure that you do not lace your shoes up too tightly if you are wearing sports shoes or any other shoes with laces. If you can, you should also get off your feet several times a day. You should take a break every hour if possible, sitting down for a few minutes, preferably with your legs elevated.
If after these changes, you continue to feel numb in your toes, you should see your doctor as soon as possible. There are several medical conditions that can cause numbness of the extremities, and many of them are serious conditions that need prompt attention. Diabetic neuropathy is one rather common problem, and if you have already been diagnosed with diabetes, you should see your doctor immediately, whether or not you change your shoes and your daily work patterns.
answered by G R