Huffster is right in SOME cases.
You can overdose on nutrients and vitamins. Taking some in large doses can actually be fatal or can cause damage.
One such case is iron intake in males, which I believe daily intake should be 8 milligrams. Overdose can cause death within a week apparently (of continuous overdose).
Some vitamins however, are fine no matter how much you take in, Vitamin C is one such example.
If you are concerned, you should look for some approved websites and see what are the Recommended Daily Values for each vitamin, check and see which of them in excess is harmful, calculate the amount you are intaking total for that specific nutrient, and judge yourself if that exceeds the limit.
Not to scare you or anything, but I don't want you to leave here with the impression of "more is good for every case", remember the cliche quote that "too much of anything (including the good) is bad for you".
Lastly, no, you just started on these vitamins correct, if there was any damage done to your body, it should not be permanent.
P.S. If I'm in the mood, when I get back to my apartments (currently visiting the fam), I'll take a look into my nutrition book and do all the RDV findings for you, just give me a list of the vitamins you wish to know more about. I could tell you what they do and the like as well.
Take care