The word reactive implies that you don't have the initiative. You let the events set the agenda. You get tossed by the tides of life. Each new wave catches you by surprise. You scramble just to stay afloat.
In contrast the image we associate with pro-activity is one of grace under stress. It is not just that you anticipate the waves, but you turn into them.
Being proactive is not a mysterious quality, it is something that we can learn to develop.
Ask
1 what do you want to happen?
2 what do you need to make it happen?
3 what could go wrong and how to be ready to deal with that?
4 what is likely to happen before it happens.