If your starter is inactive, that is, not reacting on feeding (by becoming bubbly), you don’t have to start all over again, there are other ways you could try.
Save a little bit of your old sourdough starter and put it in a clean glass jar. Feed it with 50 g (1.7 oz, not fluid!) of filtered water and 50 g (1.7 oz) of flour. Add a little bit of honey or grated apple. Stir and cover with a lid or cling wrap. Let sit for 24 hours, then add another 50 g of filtered water and 50 g of flour. Wait 24 hours. If it is not bubbly by now, pour out most of the starter, and save some in a clean jar. Feed with 50 g of water, 50 g of flour and honey. Wait 24 hours.