It depends of what you are loading as to a good sub to get you by for now. On line purchases of some powders can be found. It will still take a while for them to show up at your door.
In the future, it might help to keep stocked a year in advance of what you plan to shoot. Once things settle down and components are available again, I suggest purchasing a little extra of everything you need to reload. Also put in orders a little more often. Eventually you will get up to the point of having a years stock on hand. Generally that will get a person through these crazy times. I also keep some factory ammo on hand to supply me with brass.
This past year I tried a few different powders for the calibers I reload for. I wanted to see if I could find a better load and to see what I could switch to if I couldn't get the powder I prefer for a while. Now it is paying off for me. I have a little of the other powders I tried that work. I hope I have enough of the powders I prefer to use.
As long as you have primers you should be able to get some type of powder to load just about anything. You would have to work the loads back up again. Bullets should become available first. Powder next and primers last. Just the reverse of how they disappeared.
For me, I have reduced the number of rounds fired per range trip. I have also cut the number of range trips per month in half. This should let me stretch out my resources until I can get more supplies.