came out for the first time to my friend

I felt like i have to share with someone what i feel because i can't keep everything I'm going through to myself, so i decided to come out to my good friend.
It took me some time, but then I saw a beautiful woman. It wasn't easy to stop look at her and I felt strange feeling in my stomach. It reminded me how gay i am, so i just told my friend "i'm bisexual" (it was very hard for me to say these words) . She was very supportive, as i expected. She said "yayy" and hug me without any hesitation, told me that she would never guess and that until i'm not sure, i don't neet tell anyone else. (I don't know why i tell myself i'm not sure!! I know for sure that i attracted to women and men). we talked about it a little and then back to normal.
i felt some relief, but after a half an hour I started to feel anxious and scared.
I told myself in my head that i don't want to be like that, and why i can't just be straight..
I started to freak out a bit. That's strange because before that, I was totally okay with being bisexual, it wasn't such a big deal for me. and now it's scary me.
Right now I feel bad with myself, but still nice to know I have someone by my side