Car is starting but very low power

I have a 2002 Toyota camry and it kept dying on me of I left the doors open or the
interior lights on in sec if i left the doors open wjen the car was off. So i figured battery
is going dead.  So i changed the battery cuz it got to where i had to jump start the car
every time i turned the car off.  I replaced the battery and now it turns over and starts
but it doesn't sound like it's getting enough power to it cuz it's idling so low when o start
it that it wants die and sounds like it's just barely got any power.  If if i push pn peddle
to give it gas it shoots rpm up but then wants tp doe when it comes down?