The nasal spray (the one they give to children) is a live vaccine so there is a small chance that it could make the person receiving it feel a little under the weather for a few days. The injection they give to adults is not a live vaccine so any illness experienced around this time is purely coincidental. It simply can't 'make' you ill although, of course, it is given in winter when most bugs are going around and so, statistically, some people are going to get ill at this time.
It doesn't prevent all strains and flu and there is a good chance you could still catch flu anyway. However, there is also a good chance that it will offer protection and bearing in mind how awful genuine flu really is, and how many have suffered with it this winter, it is still (in my view) worth having.
Myself (pregnant), my husband (paid at Boots) and my son (had it at the GP surgery) have had it this year and I am glad we did. So far, touch wood, no flu in our house and I am reassured that even if one of us did catch it, and become very poorly, that I did everything in my power to prevent that.
People worrying about conspiracy toxins are usually basing their opinion that comes from America where they use different ingredients in their vaccinations and operate different vaccination schedules to us.
In terms of the specific flu vaccine, it won't necessarily be a case of life or death making a decision either way for you. You haven't mentioned any issues with your immunity etc. Some people with compromised immune systems do die from flu but healthy people can usually recover well. However, I hate being ill, I really can't bear it so I will try anything in my power to avoid it. I am generally very pro-vaccine.