If you're really uncomfortable with them is there anything you could use to distract yourself immediately these thoughts come up e.g phone someone up for a chat (you don't have to tell them why!) something that you have to pay attention to if only for a little while. The thoughts may well keep on coming but become less absorbing or regular if you get into the habit.
Are you in a relationship with anyone at the moment- if not then when you are the thoughts may lessen if its any consolation. If you are is there anything you could think of to make the relationship more "stimulating".