It calls to you from the middle of a deep slumber. That annoying sound that just won't go away until you stop hitting the snooze button and get up to start the drudgery of another work day.

And then one day it stops calling.

That's a welcome change when you first retire, as each day belongs to you. There are no meetings to attend and no annoying co-workers or customers to be bothered with. But then having nothing to do starts to get old. The house can't get much cleaner, and you just saw the grandkids last weekend. Soon you find yourself a few weeks or months into retirement with a spouse who is at their wit's end, wondering how the two of you will survive your retirement.

The honeymoon is over
We all dream of the day when we stop working for someone else and start living our lives to the fullest. And yet when that day finally arrives, we realize there is a lot of time to fill. When we're working, a third of each day is filled by commuting, completing tasks, and interacting with other people. In retirement, that third of the day can be an empty void. And all of the "honey-do" projects will be done sooner than most retirees realize.

This can lead to big problems down the road. A 2013 study by the U.K.'s Institute for Economic Affairs found that 40% of retirees suffered from clinical depression, with 60% reporting a decline in health. Having nothing to do can make it tempting to spend money to fill the void. However, taking unplanned trips or making unplanned purchases can eat into a retiree's budget, which is likely already lower than it was during their working years. Overspending is just one of the many risks that retirees face in retirement. This can make that first year challenging. To help avoid this risk, here are a few things that retirees can do to fill that time void to the fullest and make retirement enjoyable.

1. Invest in yourself
Learning a new skill or taking on a new hobby can open up a whole new world to you. It can be both fun and inexpensive. For example, eating out every night on a fixed income may not be in the cards, but learning how to cook a new cuisine opens new dining options at little or no extra cost. And for many, it can be a highly rewarding experience.

There are countless library books and YouTube videos to help retirees get started with a new hobby. The options are endless. Sewing, gardening, woodworking, and painting are just a handful of the many fulfilling hobbies that retirees can learn.

A local craft store, for example, is a great place to start searching for a hobby. Craft stores typically offer beginner-level classes on a range of potential hobbies that you can check out for little to no cost. Meanwhile, websites like Groupon and Living Social often offer discounts on various classes and workshops that can allow a new retiree to inexpensively try a few hobbies and find one that fits. 

2. Invest in others
Retirees tend to struggle with the sudden drop-off in social interaction. With meetings and sales calls no longer on the docket, retirees begin to miss the social interaction found outside of family. This is where volunteering can play a vital role in retirement.

Retirees finally have the time to give back. They can mentor kids or young executives. They can help out at a local nonprofit or hospital. They also have the time to help family and friends. In giving back and investing in others, retirees can find the fulfillment and social interaction they crave.

While there are likely plenty of volunteer opportunities in your own backyard, organizations like SCORE, AmericCorps' Senior Corps, AARP's Create the Good Program, and VolunteerMatch are some of the many volunteer resources that can be found online. Meanwhile, HowStuffWorks has a great top 10 list of volunteering ideas for retirees.

3. Start down a new path
Some retirees aren't yet ready to fully retire. However, with plenty of time and a secure source of income, retirees are in the position to pursue a passion that was inaccessible during their working years. They can start a business or get a job in an entirely new industry that can bring fulfillment along with some extra income.

Simply planning to start a business consumes a lot of time. It requires countless hours of research and then more hours preparing a business plan and then carrying out the vision. One option for a retiree is to pursue owning a franchise that has a proven business model in an area where the retiree has an interest.

Retirees who would like to travel but are limited by budget should consider becoming a travel group leader. This can be as simple as recruiting a group of friends, former colleges, and family to a tour group and working with a tour agency to set up the trip overseas. Most tour agencies will offer a discount to the group leader for each person recruited to the tour, and if enough recruits sign up, it's possible for the leader to earn a free trip. It's a "job" that could be repeated year after year, with a new destination each time.

Final thoughts
More often than not, retirees have trouble adjusting to their new lifestyle. Few are prepared to have nothing to do and no place to go. However, by investing in themselves, investing in others, and starting down a new path, a retiree can not only survive, but thrive in their first year of retirement and beyond.