My 2yr ld is jealous of the new baby help?

i just had a baby boy 7weeks ago and my 2 1/2 year old daughter is becoming jealous and i think doing things to lash out for attention.at fist she was happy about having a little brother but lately she's been acting up. and sometimes she will even try to punch or hit the baby. shes never been this way before shes usually such a good girl. shes also been throwing herself to the ground and ccloses her eyes and doesnt move like she is trying to pretend like shes lifeless. i know this is because of the new baby. i try to still show her as much attention as i can but im doing this on my own so i dont really have someone to hand the baby over while i spend seperate time with her. i need help i dont wanna see her upset and like this or feel i love her less or that she isnt my baby anymore. what can i do any suggestions or anyone been in my situation before??? please and thanks.