Did you use any filters? Coloured filters can be used to boost contrast. The most common filters for B&W are yellow and red filters, followed by green and blue filters. The red filter will dramatically darken any blues, so the blue sky turns in a very dark colour. Basically, any coloured filter will lighten its own colour while darkening its complementary colour in the colour wheel.
A common saying for B&W is to expose for the shadows and develop for the highlights. Basically, when metering a scene, try to see which part of the picture has the darkest shadow in which you want to retain detail, and expose for that. When developing and printing, the opposite occurs and you look at the highlights where you don't want to get blown (I'm not really an expert, so please correct me if I'm wrong).
So lack of contrast may occur if you meter the scene wrong, or if the developer develope it wrong. I sent my first few rolls of B&W to 2 different developers (one a high street shop, and the other is a mailer from Ilford), and the film which I sent to Ilford, came back very good while the high street shop gave me muddy prints, so the developer is very important (especially if you are not developing yourself).
I personally prefer Ilford HP-5 and the classic Kodak Tri-X, both of which have good latitudes and excellent grain for the reportage look.
Negatives can grow mouldy too (like lens), so its best to dump them in together with the camera into the drybox if you have space.
Hope that helps!