I have a week erection to were the shaft is then with a big tip then theres times where my shaft matches the tip why and how can i keep a hard erectio?

Here are some ...: The specifics and sequence of events of the Q are unclear so it's hard to offer an answer to the point. But I assume you suffered from a one-week long persistent erection. If so, you go priapism, which was not timely attended and professionally managed, and would result in much expected impairment in erection. If you wish to explore more on this subject, go to http://en.wikipedia.org/wiki/Priapism