I recently moved across town in Los Angeles, California. My small 3 foot high Meyer lemon tree was happy for the past year on the balcony of my apartment and got a fair amount of sun from mid-morning until 2-3pm. In the new home, it is in full sun on my rooftop. We had a heat wave with temps in the upper 80s for a few weeks and my tree started yellowing at the tips of the leaves. In its new location, I wasn’t watering it often and it went a few weeks without water. I noticed the yellowing and started to water it more, gave it plant food (general food, not citrus) weekly for 2-3 weeks, and picked the 5-8 lemons that were present. It went from bad to worse and all of the leaves turned brown and crunchy and shriveled up along with any flowers. Is it too late to save it now? Did I kill it with food or under watering it or both?