I started around the same spot in my studying. I found that I certainly needed to brush up on the fundamentals, which I have largely done through MGMAT's five quant guides. They also have a more basic fundamental guide, but if you're in mid-30's, IMO, you don't need that. After going through all of those guides (as well as OG alongside them), then you should be in low 40's, at least. Then, progress to GMAT Club tests
to get yourself into high 40's. That's my plan which I feel will work for you as well.