Can God speak to me through dreams?

As an experiment, assume that it is "god saying itll be ok". Then compare this prediction to what actually happens. If you and your girlfriend continue to experience rough times, you can deduce that it was not an infallible god speaking to you. However, if your relationship improves you have the choice to credit either god or the projections of your unconscious mind.

If there were a god it might be saying you'd better call and apologise.

Maybe. But things generally don't "just work out". There has to be elbow work and change,