In outlook, press the file button on the ribbon in the top left corner

 From this menu, you press the options button towards the bottom on the left hand side

The Outlook Options window will pop up. Select Add-ins on the left navigation menu

At the bottom of this menu there is a line to Manage the addins. If you use the drop down to select Disabled Items and press Go it will bring you to the screen to re-enable any add-ins you need.

Re-enable any line in the Disabled Items screen and you should be back up and running.