There is nothing wrong with thinking! Thinking is wonderful! Without thinking we would be inanimate objects incapable of doing anything! Meditation IS the acceptance of thinking, the witnessing of thinking and the letting go of attractive of difficult thoughts that might otherwise linger.
So, it's important to know that nobody is saying that thinking is bad:)
And of course, there are many times when it is very necessary to reflect on things that have happened in the past, or to plan for things in the future. But we can either do this in the present moment, fully conscious of those thoughts and driving that chain of thought, or we can do it without any awareness at all, utterly distracted, and essentially being driven by the thoughts themselves, drifting, being carried - so no longer in control of that thinking process.
Thinking is fine, and you are more than welcome to do as much of it as makes you happy, but it's important to recognise that many of our feelings arise from patterns of habitual thought, and so if we allow the mind to do whatever it wants, then we should fully expect those feelings to arise again and again.
So, you may well want to a bit of time aside to focus on these particular things or even to allow the mind to drift a little.
But it's also important to recognise that we cannot be lost in a daydream and experience the present moment at the same time. One is asleep and the other is awake - in terms of awareness. So, the question to ask yourself is "do I want to live life fully?" If the answer is yes, then it is really quite straight forward.
As good and attractive as those daydreams may be, they do not even come close to the experience of living one moment after the other - in my humble opinion. To begin with it may not feel this way because it will feel like a lot of effort is being made, but after some time it become second nature and is the most natural and wonderful feeling in the world.
For more help on this question and many others, please check out our videos from Andy on our YouTube page here.