It is normal to lose a large number your first week. Maybe even your second week. But thereafter, 1-2 pounds a week is considered the healthy range. There were a few weeks where I didn't do anything differently and lost under a pound. So I understand where it is disheartening for you.
But you shouldn't be disappointed if you only lost a pound. That is quite normal actually. My suggestion would to be keep doing what you are doing and the pounds lost *will* add up eventually. Also a good suggestion is to focus on five or ten pounds at a time. Set yourself mini goals and come up with a type of reward system.
I had a fair bit amount of weight to lose as well and I really encourage you to celebrate all your successes, even tho it might not be the exact amount that you were hoping for.
It sounds like you are doing well. Keep being determined