olive sapling issues

Hello, can you please help me problem solve what is wrong with my olive tree.

We have moved it into the direct sun area (Southside)
We are going to test the topsoil 2in deep for dryness when watering
We are ordering some MiracleGrow cactus, palm, and citrus mix to help with drainage 
and possibly order a grow light (any suggestions?)
Is it a disease?
Is it overwatering/ underwatering?

Is it sunlight deficient?

Please send your opinions/knowledge this way