Use two pillows. One under your ass one under your back (also levels you).
I have a slightly twisted spine so I need support.
Also when you get good at press ups, try doing them on your knuckles. When you can do 50 on your knuckles you can class yourself as a modern Rocky Balboa
Congrats on the weight loss, it's more than impressive, two questions tho:
1) How'd you get that much weight on?
2) What motivated you enough to make the change, and kept you going through it?