If you put your $ 5,000 into a riskier asset class such as stocks (ie a stock mutual fund) then in 6 months your investment might be worth more than $ 5,000 or it could be worth less than $ 5,000 (possibly a lot less).
Lowering the amount of risk in your portfolio by increasing the safer investments (ie more bonds, lessstocks) will help you sleep better at night if that is a problem.