Do blockages happen this quickly?

Hello, I am a 41 yr.old female. In Feb.2011 in ER, they told me nothing was wrong with me...all tests are normal...but because I keep complaining...my cardiologist said he would come in the following day and do a cardiac cath.On the morning of the cath. my cardiologist told me..."I'm sure it's not your heart...I know it's not your heart but we will just do this cath. anyway just to get it over with...you had a cath 6 years ago and it was fine....So, I know it's NOT your heart."  As soon as he started, the cardiologist said, "oh, you have 2 blockages. Well, I don't do angioplasty so someone else will be right in...and he LEFT. The next dr. comes in and says, "he say u have 2 blockage....u have FIVE". He put in 4 stents and opened one blockage with a double balloon.
I was fine until April 2011, when I began experiencing the same symptoms as I had in Nov 2010 & Feb.2011. Cardiologist #2 did another cath....said "everything was NORMAL"....which later on I was told "it wasn't critical at THAT time.
Still complaining all the way to June 2011, the office decides I need a stress test. I went to ER again for same symptoms, they would not release me until my cardiologist saw me. Cardiologist #3 came in and told me my stress test was positive and that he needed to get me in the cath lab STAT. So, another stent is placed and I am "FINE". 6 weeks later, I am just getting home from the hospital, which I was at from Monday until Thursday. I had two more stents put in, now I have 7 stents. I still have 2 arteries that are 20% blocked...one new one and one where they put a stent in in Feb. My question is, how quickly do these blockages happen? I mean since they just put a stent in in June and now in July a new blockage (90% blocked) occurs.
I appreciate any input you may have.
Thank you.

[CCF HeartMD6]

Blockages in coronary arteries (or re-blockages within stents) can occur at any time and may be the result of a number of factors including where the original blockage was, the type of stent that was used, how the stent was placed, medication compliance (i.e. clopidogrel), and the substrate (i.e. patient with multiple risk factors, etc). Unfortunately, it is impossible to say for certain by just results of a catheterization and not actually seeing the films.