Congrats... We are proud of you..
The sheer effort and concentration you exerted on that first flight was immense, hence subsequent flights suffered from brain fade. This is quite common in learners, (we have all been there) more so with helis, it soon gets better. The secret, as I tell all the people I have trained, is take a break, relax, and calm down before you go again.
Regards
D.D.