Do you think you may be dong too much too soon? Or too much with the time you have available? When you said you were “squeezing in” training and trips, that made me wonder that maybe the load is too high, whether that load is mental or physical.
I’ve made those types of mistakes many times myself, so that’s what made me wonder.
Also, in general when you’re not sick, 80-90% of your training should still be easy (below your aerobic threshold, or limited by breathing through your nose). Would that describe most of your training?
Frequent illness is typically a sign that the total stress load is too high, including physical and mental components.
I hope that helps.