Hairloss :(

From what I've read on the extensions forum here, extensions are not a long term solution, since they tend to cause hair loss with damaging glues and such.  Hair loss after childbirth is normal, and it may right itself after enough time has passed (I haven't been through that myself, but have heard it can take a year or two).  Take good care of the hair you have with a moisturizing routine, and don't do things to it that are damaging (no heat styling, chemical processes etc.). 

How long is your hair?  Silicone buildup may be part of the problem if you are using shampoos/conditioners with too many silicones and if your hair is somewhat long (won't be such a problem for shorter hair because it gets trimmed off before it causes much trouble - also won't be a problem if there is a clarifying shampoo in your routine to remove the silicones periodically before they get old and start to chip on your hair).