Pharah improvement and hero advice

Hi, sojourn main here.

For context, I play for Ohio Wesleyan Crimson as like a backup,

I mostly main Sojourn, Soldier and Bastion, but I'm trying to branch out into more DPS/Support heroes to be more useful (read: get more playing time) to my team for this upcoming season. I've been trying to learn Pharah, but I typically tend to run around like a headless chicken whenever the enemy sojourn/ashe/soldier focuses on me.

How do I fix this?

In other words, how do you not panic when diving/dueling?

As Sojourn/Soldier, it's easy b/c of the healing beacon/disruptor grenade, but Pharah doesn't have that.

In addition, are there any heroes that are relatively easy to pickup/learn for a competitive setting in 10 days or less? I don't need to be grandmaster, just as good as a gold player.

Thanks,

E