1. Depression is disqualifying for any medical. If the depression is resolved, there will be a waiting period, after which they will require that you get an exam to prove it. Only then can you get a medical.
2. Any unexplained loss of consciousness will be disqualifying. They will want an explanation, or a lengthy waiting period with no recurrence (years). They would probably accept acute illness (ex. flu) or not eating as an explanation.
Most people get over motion sickness when they start flying. May take a little while. If it wasn't very severe as a kid, you'll probably get over it quickly