Nice recap! I’m starting the journey into ultra distances soon having worked up my long runs and done one marathon. Slow but steady is my plan but I went through a similar experience with half marathon distances last year. Coming back from a broken ankle I’d only ever run 4 halfs prior to the break and experienced them as extremely challenging. During rehab I watched and read a lot on nutrition/hydration, bought a Salomon pack and started off. Now a half is part of my weekly long run at an easy pace and they seem normal. TIme to go your route and make the marathon feel the same way!