Hey there!
First of all, do not panic!! I was literally in the same position as you this time last year. I barely did anything for my PIP during the holidays and didn’t officially start my PIP until March 2017. I was one of the last ones to start but ended up being the first one to finish my PIP (around a week before official submission)
The way I motivated myself was reading secondary information (books, articles, etc.) in order to create my questionnaire: my very first primary research methodology. Once you get your questionnaire going, you’ll finally realise ‘Oh shit. I have to get more shit done’.
The PIP due date is not too long away now (should be due around July, the week when Catholic Trials are on!). So the earlier you start your questionnaire (or any primary research really), the more motivated you will feel. You will also feel a sense of achievement when you complete a part of your PIP.
As for my timeline, the way I did it was to get one chapter done every three to five weeks. Then submit it to my teacher for her to proofread. It is so crucial to submit stuff early to your teacher because they are more likely to give excellent feedback and suggestions because they’re not under pressure to check other people’s drafts. Take advantage of your studies to do your PIP and get the feedback during your assigned PIP lessons! I also made sure I got at least two primary research methods every two to three weeks.
TL;DR > Start your primary research early. Read secondary research. Submit all your drafts. Get one chapter done at least three to five weeks. Term Four (same term as trials) should be the term where you are finishing up your PIP, not writing the first draft of your chapters or your introduction etc. You do not want to be doing your PIP during the weekend before trials.
Good luck!