Numbness in feet can be caused by having the shoes to tightly laced, try that first because it's cheap to do.
Second cheapest thing to do is to adjust your cleat position, if you bought your shoes at your LBS they can do this for you and should do it for free, my LBS does. They will usually align it with the ball of your foot and for some people that can cause numbness, before moving the cleats mark their position so you can return to that spot if necessary, so try moving the cleat back toward the heel in small increments and test each time you move it, and stop moving it after you found your happy spot; if after moving it a bunch of times and you still have the issue then move the cleat back to the position I had you mark, then go to the below step.
Your shoes could be the wrong size, usually too narrow which most Americans have wider feet than their European counterparts which is what most shoes cycling are made for, but there are wider shoes on the market nowadays. I always suggest you go to an LBS to buy shoes and not over the internet, at least for the first time. The LBS will have ways to measure your feet to get the correct fitting shoe. Shimano, Bontrager, Sidi, Specialized and Giro are usually found at most LBS's and all of those have wide foot models; there are a couple of other brands too like Lake, Northwave and Bont, but those are very difficult to find at most LBS's. There is a lot to consider when getting the right fitting shoe, toe box room, foot width, and heal width, and different shoe manufactures will make that stuff all different which is why it's important to go to an LBS for a shoe. PLEASE, don't go to a LBS and they find a shoe for you and you walk out not buying it because you're going to go online and buy it cheaper, if the sales person spent all that time with you to find the right shoe BUY IT from them, the salesperson usually gets a commission or a bonus for selling, so don't waste their time and money when they could have gotten a sale from another customer by not buying it. I understand if they don't have something you like, fine, go to another LBS and see what they have. I'm not a hardnose buy it at an LBS guy to save the earth by keeping LBS's in business, but if I go into a bike shop and I ask them for help on a product I will buy it from them, but if I know what I want and I can get it cheaper (including shipping and taxes) then I will buy it online. Anyway, you could be having a shoe issue.