I’m going out with friends for 4 nights soon. Forecast has temps dropping to 21F one night. The last time I camped at this temp I froze my butt off. I have a warbonnet BB with. 20 degree warbonnet yeti 3/4 UQ, a wiggys sleeping bag rated to 20 and an inflatable sleeping pad I put inside the sleeping bag to prevent it from moving around. With those 3 items I was on the verge of hypothermia. I’m considering pitting a SOL thermal survival bag inside the sleeping bag as well or trying to use an old sleeping bag for a makeshift additional UQ. Any other suggestions to keep a little more comfortable at night?