Is this because my macbook doesn't enough of harware power or is there something that i'm doing wrong.?
In short ...Yes and yes
Some of the plugins that you are using are fairly high on CPU and RAM usage (Studio drummer, Scarbee etc).
To try to improve the situation:
Increase the I/O buffer size (increases latency but reduces CPU load)
Make sure that you have an empty audio track selected whilst playing back
Use Bounce in Place (or Freeze) to covert some of theses High CPU instrument tracks to audio
CCT is correct, bouncing the plugin tracks to audio once you are happy with them should help a lot. There is one thing that I found about Bounce In Place (I think that is the Bounce option that I used but I am a Logic newb so...) is that, while the Arrange track is replaced with and audio track, if you look at the All view of the mixer the original plugin channel will still be there with the plugin still loaded--you need to delete that channel or remove the plugin (you can save the channel preset before doing this if you want to be able to recall it later) to get the CPU back (Freeze may be an option too but I haven't used it.)
The other thing that can really save CPU is increasing the Audio Buffer size. This can have a drastic affect on the CPU but it will also add latency to your live input monitoring. If you are in "post production" mode and just working on editing and mixing OR if you can use hardware direct monitoring from your interface or mixer OR you are composing with programmed loops the increase in latency won't matter.
Some other strategies to use to save resources:
I don't know about your drum plugin but mine allows me to only load the kit pieces that I need. I have a 12 pad e-kit but Superior kits typically have many more instruments--I can just dump the ones I don't need which saves RAM.
Use Aux buses to share Reverb and Delay plugins. If you are using a Reverb on each track or within the plugins on those tracks try setting up an Aux Channel for a shared Reverb and Delay and use them instead.
Use Buses as channel outputs to group like instruments that could share processing. If you find that you have similar/duplicate signal chains for things like rack toms, floor toms, backing vocals, doubled guitars you may be able to change their outputs to a common buss and move a single instantiation of the plugins to that Aux channel and save resources.
Obviously your Sample Rate is going to have a huge affect on resources--I am always tempted to record 96khz but my current iMac isn't ready for it particularly because I monitor through Logic so I need low latency. of course,doubling your Sample Rate will cut your latency in 1/2 so you can save resources by doubling your input buffer to balance latency and resources--or vice-versa if you are changing from 96khz to 48khz.