Why Does One Get Unpleasant Side Effects After Taking Loestrin?

I have been taking loestrin 24 fe for over three years. I have had unpleasant side effects, but my current ob/gyn told me that I am already on the lowest dose of birth control pills. He recommended that I take a month off the pill to see if my side effects went away. Well I did take a month off in august, and my body felt really good. I also felt better mentally. I wasn't moody. However, since I started the pill back in october, I have been feeling really depressed when I start taking the iron pills. These depressed feelings go away once I start taking active pills again. What should I do?