After the fclose
I've lost many, many girls quickly after closing them. The bad news is I have not found a pattern that is always effective. The theory of making her wait longer might work. However, I've found it means less total lays, so I am not an advocate of it. Plus, it's not applicable to your situation.
Definitely, DO NOT turn into a wuss. Acting overly wussie is the absolute worst thing that can happen, and the woman will get tired of it very quickly. She may even think it's cute for an extremely brief period, then it will just start to annoy her. This will get you next'd very fast.
Don't give up your normal activities such as going to the gym and stuff. Doing that will show you have a weak frame and place too much emphasis on her. Keep your studies and work going well. Make yourself in a positive mood right before you answer her calls and go see her. Try using anchors such as the same incense when she's in a really great or sexual mood. Make sure you spend some time with her, and let the phone go to voicemail rather than answering it in a bad mood. Those things should help. I wish I had a better answer, I'm searching for it myself.,