Social Security won't provide enough income for you to live on during retirement. In a best-case scenario, those benefits will replace about 40% of your previous earnings if you took home an average paycheck, but most seniors need around double that sum to maintain a decent lifestyle. And unless you're privy to a pension or another clear income source, the difference will likely need to come from your retirement savings.

Unfortunately, most Americans are behind on the latter, according to a new survey by GOBankingRates. In fact, 45% say they have no money set aside for their golden years, while 19% expect to retire with less than $10,000 (which, let's face it, is effectively the same thing as having no nest egg at all).

Glass jar with coins labeled retirement


But it's not like U.S. workers are neglecting their nest eggs for no good reason. In fact, in the above-mentioned survey, those behind on savings have some pretty compelling excuses for being in that situation. Here are the top three reasons why Americans aren't doing a better job of saving -- and how you can overcome them to salvage your golden years.

1. "I don't make enough"

It's hard to fund an IRA or 401(k) when you don't earn a lot of money, and you need every dollar in your paycheck to cover your basic expenses. The solution? Boost your earnings with a side hustle. An estimated 14% of workers who hold down a second job do so for the express purpose of building retirement savings.

Imagine you're able to earn $200 a month from a second gig, whether it's waiting tables on weekends, writing web content at night, or house- or pet-sitting as time allows. If you were to sock away that $200 a month in a retirement plan over 30 years and invest it at an average annual 7% return (which is doable if you load up on stocks), you'd be sitting on a cool $227,000.

2. "I'm struggling to pay the bills"

Funding a retirement plan may seem next to impossible when you're barely managing to cover your essential expenses, like housing, transportation, and food. If that's the situation you're in, the solution could boil down to lowering your living costs, whether that means downsizing your home, unloading a vehicle and relying on public transportation, or pledging to cook solely in your own kitchen rather than dine out until your financial picture improves.

Following a budget will also help you better manage what limited income you have, thereby making it feasible for you to eke out modest savings month after month. And as we saw in our previous example, saving and investing $200 a month can go a long way over time.

3. "I'm prioritizing paying down debt"

If you're carrying a lot of debt, it makes sense that you'd want to eliminate it and then start funding your nest egg. This especially holds true if your debt comes with a high interest rate attached to it. The problem with this approach, however, is that if you wait too long to start building your nest egg, you'll lose out on years of potential growth on your money.

A better bet? Work on paying off debt and funding a retirement plan simultaneously. At the same time, find ways to make your debt less expensive so that you have more money left over for your IRA or 401(k).

If your debt stems from student loans, for example, refinancing is a good option to consider, especially if you borrowed from private lenders to attend college. If you refinance to a lower interest rate, you'll reduce your monthly payments, at which point you'll be able to sock away the difference for your golden years. The same holds true if you're carrying credit card debt. You can try transferring your balances onto a single card with a lower interest rate, thereby lessening that monthly burden and freeing up more cash to save for the future.

Saving for retirement isn't always an easy thing to do, which perhaps explains why so many Americans are behind. If limited earnings, staggering expenses, and high levels of debt are preventing you from funding your nest egg, it's imperative that you work past those issues to carve out money for long-term savings. Otherwise, you'll risk struggling financially later in life, and winding up miserable for it.