Hello hoobastank7000,
First I would liek to tell you not to panic. Second, there in no Lithuanian embassy in Africa except in Egypt, so you need to make a trip there. Also I do not think they can extend your stay in Lithuania, unless you are doing something that is not a threat to the state (this is what the Lithuanian Government says) so you need to statr a business, or attend a university or if you trully love your girlfriend, you can marry her (but please do not marry her just to be able to stay in Lithuania, she is a person and should not be used).
If you need more advice, you can ask more questions.