Moms of 2

Just need some inspiration that I'm not going to fail. My mom (my support system) told me yesterday they are leaving this upcoming Friday for 4 months to go across the country. My 2yo is still very dependent on me, and I have my (almost) 3 month old. Their naps and feeding times overlap, which is why I've had help everyday trying to keep them on their schedules (it's truly worked pretty well). Now I have a monkey wrench (which is where I felt like I was when my husband went back to work, but I KNEW I had some support to help me) and I don't know what I'm going to do and already feel like a failure and a bad mother. How do you guys do it (if you're doing it alone)? When I've had to wrangle them by myself for most of the morning, I've literally just sat my daughter in bed with me and let her watch YouTube to try and keep an eye on her while rocking the baby to sleep. I just feel like that's all I'll be doing, because we're in the shitty nap stage, and I end up coming in here to rock her to extend her naps. Do I give up on that? It all feels so overwhelming and too much right now.