Cardinality of a conjugacy class

Question

Let $G$ be a non abelian group of order $pq$, where $p$ and $q$ are primes and $p$ divides $q-1$.

I've shown that :

1. There is a unique subgroup of order $q$ in $G$ : it's the derived subgroup.
2. The center is trivial.
3. There are $q$ subgroups of order $p$, and they are conjugate to each other.
4. Every element of order $p$ has exactly $q$ conjugates.

Now I'm asked to show that an element of order $q$ has exactly $p$ conjugates... And I need help, please :)