Login script for bash not loading

I am very confused about the login script for bash. I have always used ~/.bash_profile to configure my bash shell. Now I am on a new system just as a user: I am not root. This system was originally using tcsh shell and I changed it to bash using the command ypchsh to /bin/sh, but it does not load my bash login configuration file and not even .bashrc. But if I type just

bash

in my terminal, my login file is loaded. What should I do to load it on login?

sample of my .profile:

# .bash_profile

 # Get the aliases and functions
 if [ -f ~/.bashrc ]; then
         . ~/.bashrc
 fi

 # User specific environment and startup programs

 PATH=$PATH:/usr/local/share/bin/:/usr/local/share/bin/idl/:./
 export PATH

 source $HOME/script.sh

 export SCRIPT_VARIABLE