Yes, you may buy yourself a Rolex watch. We are taught in the Talmud that God decides at the beginning of each year how much money you will have that year. As long as you have given the correct amount to charity, the rest of the money is yours to spend as you wish.
However, if you want to feel good and not “guilty” about buying such a luxury item, perhaps you could entertain the idea of giving an equal or generous amount to charity (in addition to normal charity requirements). You do not have to give it all at once (as it is rather a lot of money!). It can be split up into payments over the space of a year instead. Enjoy your new watch – if you choose to get it – and may you always have ample wealth and wisdom to choose to use it wisely.