It is very late for you to salvage this project and, perhaps, this employment situation, and as some of the other answers provided some ideas which might help, I'll rather provide some guidance so that you (or someone else) can avoid this situation in the future.
First, and most importantly, you need to have open, honest, and frequent conversations with your manager. You need to let him know where you are having difficulties, where you are stuck, what kind of help you need. To quote another answer I've written "your manager's job [is] to do his/her best to give you the opportunities to succeed". That might include guiding you on how solve a problem, pointing you to the proper resources, assigning more people to the project, or maybe finding a project which better suits your current skill/experience level. If you come to him 5 months into a 6 month project, and say you've made no progress, there is very, very, little he's going to be able to do to help you.
That said, your manager is likely a very busy person, and so if you aren't actively communicating the honest state of the project to him, it is quite possible that he assumes that you don't need help and that the project is going smoothly - it's also quite possible that you just completely fell off his radar. The onus is on you to seek him out and keep him informed.
The second piece of advice I'll give is to make progress every day. Even if it is very minor, even if it is just to schedule a meeting, send a few emails, download and install some tool you need, etc., you should make sure that you are making some forward progress every day. This is important because, besides the obvious of pushing you closer to the final goal (even if only infinitesimally), it improves your psyche - it make you feel like you aren't stuck; it keeps your spirits up.