score:5
Nope, not a problem. You can re-enter the US anytime until the visa expires. Though irrelevant in your case, if only travelling to Canada/Mexico for max 30 days, you can even return on an expired visa.
Once your visa expires, it is only next time you travel abroad (other than to Canada/Mexico for max 30 days) that you need to get a new one. In that case, make that trip slightly longer and arrange an embassy appointment there in advance. Alternatively, you can pop over to Canada/Mexico anytime after expiry specifically for the purpose of getting a new visa.