Is it normal to always feel quite nervous before a game

Hi, new poster here. For some reason I always feel quite nervous or anxious before I get into a game. It's weird that I"m feeling this way, despite the fact I've been playing and studying the game for quite some time - playing regularly for about 5 to 6 months. I took a break and just started playing again. The last three days, almost three days straight, I've done incredibly well. I've gone to the same casino, the busiest one in my city where there's always 10 to 12 tables playing. Anyways my first day I bought in for 65$ at a 4/8 table and left after about 4 hours with 170$. A day or two later I bought in for about the same amount at the same kind of game and left with 275$. And just last night I bought in for 170$ and left with 350$. So what's there to still be nervous about, it doesn't seem like a fluke and I've had varying degrees of sucess in the past.

It's like somehow I have the builtin mindset that it's not going to last, even though every game I play the same way that's been sucessful for me. That is I'm a tight player who play selectively agressive. When I've sensed weakness I've semibluffed and won more than a few pots. I don't usually completely bluff, I know when to fold, most of the pots I win are when I have the best hand. I can also play loose but only when I feel it's a decent hand my opponents won't put me on and only when the pot odds and odds of improving my hand make it worth playing.

I'd also like to add I'm not worried about my opponents getting a read on me. I'm currently reading a book called Beyond Tells and I've watched the video Mike Caro made based on his book of tells. Besides that I can be pretty expressionless when I want to be, I switch up my styles frequently going from tight to loose to agressive and back, and I try my best to act the same way whether I'm betting with a good hand or playing a draw or semibluffing.