My libido is on a decline...help!!?

I am a 38 year old male, married for 17 years with 3 kids under the age of 12. My wife, after 17 years of marriage still looks gorgeous to me. I am attracted to her and I know I'm a lucky man. Unfortunately, I'm not the tiger I used to be! My libido has been declining and its beginning to bother me. Yes, I'm slightly overweight and being a stay at home dad, I might be somewhat stressed but is there anything I can take over the counter for this that really works?? I have access to Walgreens, GNC, Rite Aid.....I really need to take care of this issue before it gets worse. And...I have no insurance, this is why I need an over the counter med. Thanks!!