Caffeine

So I've been lethargic and brain fogged all day for no apparent reason. I just realized that I haven't had coffee in the last 2 days. I just looked it up and caffeine withdrawal can last up to 2 months (for heavy users). Should I just cut my loses and grab some coffee? Also, how many cups do med students tend to drink in a day?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums