First off, SMP is not necessary and could easily end up hurting rather than helping. Your GPA is sufficient for mid-tier MD schools and all DO schools.
Based on the descriptions of the schools you applied to you may have skewed too strongly to your reach schools. While your other stats are excellent, the GPA is fairly low by T20 standards. I'm not saying you're DOA, but it's just going to be unlikely. Additionally, applying late to only a few DO schools (depending on where they are) might not have been advantageous.
I don't think you need to continue working in the lab if you don't want to; you've already accumulated enough hours for any medical school. Many schools continue interviewing into the early spring so it's too early to give up hope yet. I'd wait until January after the holidays and send out some letters of interest if you haven't heard anything by then.
Other than that, there's nothing for you to improve for the next cycle other than your school lists and the timing of your applications.