I love diet Pepsi a lot more than regular Pepsi - it's just as good as the sugary kind, in its own way. If you really want a diet drink and it'll help curb some of your cravings, definitely go for it. The beginning is always hard but it DOES GET EASIER, I promise.
BTW I'm one of those people that absolutely cannot do diet drinks. They stall me. Can't even look at them. So, there are some of us that just can't. There are no absolutes in dieting. Some things work for some people, some don't, but everything doesn't work for everyone equally and I cannot have diet soft drinks (or any artificial (or real) sweeteners) or fruit. Yay, lucky me.
It's OK though, life goes on.