Am I charging enough?
The fact that you’re asking yourself this question means that you feel like you’re cutting yourself short. You’re not quite sure what you should be charging, and so you used the technique any young and eager creative would to get your foot in the door—charge whatever their budget is, or under (which usually isn’t much if you’re just starting out).
Instead of wondering if you’re charging enough the next time around, find out what ease of mind you’ll be giving your client. Charge for that instead.