2 Months Natural TTC; Lining Too Thin?

I'm super paranoid about these 2 months that I'm going au natural TTC. When the RE was looking for the fetus at my 6 week ultrasound, he mentioned that my lining was thin. My periods have gotten super light over the past year or two. (This month it was 3 days of light bleeding). So, now I'm afraid that my body just cannot sustain a pregnancy without injectables. I hope that's not the case, though. I'm so broke, I'm really praying for another miracle BFP - this one in the uterus.