Sometimes taking time off, even up to a few weeks, is the BEST thing you can do. Gives the joints and the CNS a break. The body is in a constant state of entropy (it wants to stay at the status quo, not put on tons of muscle...which is why if you don't work out at all and are a natty, give it a couple three years and you will probably look like you did before you started lifting weights). So depending on how long you lay off, you may lose some mass. But muscle memory is a great thing and you can put it right back on in no time. I've done this in the past...taken up to a month or two off to give my body a rest. Then I hit the gym hard again and put back on my previous gains in a few weeks. I've noticed when I do that, my body is more receptive to putting on even MORE gains than I had gotten before, strength-wise and mass-wise.