Sadly, aerobic capacity drops off faster than about any other physical attribute when you lower or remove the training stimulus. There was a study done many years ago that showed that one week of bed rest resulted in a 50% drop in aerobic enzymes in the mitochondria. UGH!
So, I think your assessment is probably spot on. You have probably lost some base fitness. The good news is that it can come back faster than it took to build it in the first place. Try to increase the volume of this light aerobic running you can get in each week. Even if that means 20-30 minutes snuck in here and there. See if you can get one long run in each week. Try doing some of your runs early in the day in a fasted state. Whatever you do, don’t give you due to frustration. Dropping the training load is only going to make this situation worse and more frustrating.