You are not alone, there are MANY threads on PPRUNE and the other forum about this - the key, as repeated by many, and proven by many a persons experience, is CURRENCY!
Don't leave it 4 weeks between each flight and expect to not be nervous.
It was always my dream to fly light I drive, to just get in and turn the key (edit: after all the planning etc) and not worry or be nervous... it took currency to give me that assurance.
Every now and then I still take a deep breath before applying power on take off, or cutting power for a descent..
I'm not alone here, nor are you. Just don't become a statistic, many new PPLs give up (for this reason, and others) and never renew after 2 years...