Lapatinib or Herceptin?

Hi all,
Originally diag Oct 2008, recurrence Nov 2010 (one small lump)in neck. Lump removed and no sign (touchwood) of any other progression on scans so far.

I’m currently on Herceptin and capacitabine. Happily, have just found out (by phone) that I have been accepted for Lapatinib. Onc has told me to stop Herceptin. Thought I was meant to have both as they work in different ways. A bit confused.

Just wondered if anyone else in this situation? How long do you have lapatinib for? Any horrible side effects?

I am due to see Onc on Tues, so will get questions answered…but wondered if anyone could help meanwhile?
Thanks,
Gail