If you only planted it two months ago, the most likely cause is a problem with water supply, as in not enough of it. Do not fertilize the tree at all while its in a critical state, but you should soak it daily with at least 4 gallons a day, or leave a hose trickling at the base of the tree for a couple of hours daily. Do that even if its raining, unless the rain is absolutely torrential and goes on for a day or two. New trees need copious water supplies for their first two years, and particularly so if you plant in spring and not fall. If the weather is hot and sunny and dry, give it more than 4 gallons, until it starts putting out new leaves, then ensure you water it properly ongoing by giving it a good soak of 4-6 gallons every 5-7 days. A little bit of rain or a few showers is not a reason to think the tree has been watered.
The other possibility is whether the tree needed hardening off prior to being planted out - if it was packaged in plastic, or had been kept under shelter or inside, then it would have done.
This answer assumes there's no evidence on the tree of any disease or insect infestation. But one question - when you planted, had you prepared the area beforehand by digging it over and adding composted material or composted manure? Or did you just dig a single hole and put the tree into it? Regardless of the answer to these two questions, carry out the watering as recommended above in the meantime if you want to save your tree.