I need help with this relationship?!?

I really really like this girl. now ive had a chance with her before and I kinda screwed it up by being to clingy. And normally im not like that with girls its just with her i just get so flustered cause i like her so much. And I was doing better this time with her not being pushy and i still am doing ok but now i txted her this morning and I havent gotten anything back and i am sitting here wondering why the hell i havent heard anything back and I know she could be busy and stuff and I just need to know what to do in order to calm down lol. If i dont hear anything from her should I txt her today or wait till tomorrow to talk to her? Thanks And any relationship advice would be great.