Need help with this hot girl I have been seeing

I have been casually dating this girl for about 3 weeks. I banged her on our first night out and since then, we have been hanging out a few times a week and texting daily. I have even banged her about 4 times since the first night and she seems really into me when we are together and even sent texts like "miss u" or "come home and hang out with me" (when I was out of town) or "I like you" as recently as a week ago.

well on Friday night (as in 2 days ago) she texted me after she finished work and we met up for dinner and came back to my place. She was tired and stayed for about an hour but she had to get home because she had her dog locked up in her apt and needed to let him out...fair enough - we made out for a short bit and I sent her on her way. I immediately fell asleep after she left.

I woke up at 7 am the next day, Saturday, and sent this: "hope you made it home ok...I passed out as soon as you left" (we had been drinking so I thought I would check to make sure she got home safe. Anyway, no response to that text. About 12 hrs later, she sent a typical whiny text "I'm so tired"

Me: "I'm shocked..."
"Oh and you left your food here by the way" (leftovers from dinner)
Me 2 hrs later: "Still workin?"

no response, which is very out of the ordinary for her. Mind you, we text back and forth daily, even if it's simple bullshit.

Next morning I text her:
"hey are you alive?"
her: "yea I just slept for like 16 hours damn haha I'm sorry"
me: "jesus christ, woman...wanna hang out this afternoon?"
her: "what did you have in mind?"
me: "Let's grab some lunch at _____ "
her: "I don't really think gonna be moving from this couch for awhile haha"
me: "No problem just though I'd offer. you watching Sopranos again?"
her: "yesss I am"

It seemed to me that she was content just being lazy all day and that's totally fine with me - I get it because I get the same way too. No harm no foul. I chose not to text anything else all day because I figured the ball was in her court if she wanted to do something. She never texted me again, even as of now, almost 36 hrs later. Also, based on the tone of her last text, I felt like I was nagging or annoying her so I just quit. I could be wrong and reading too much into it but that's what prompted me to cut off texting for the day.

Another thing - this girl is always saying "Im tired" "Im exhausted" and even she AND her friends always joke about how much she sleeps so while I think that's kinda weird it might be no big deal -that's how she is. What is concerning me is her pretty much ignoring my texts from the night before and having absolutely nothing to text to me between now and then. This is the longest we have gone without texting and I have been strong all day and resisted the urge because I feel the ball is in her court and I don't want to be needy. I also have a long history of being impatient and overanalyzing everything so I guess my question is multi-faceted:

1.) Should I leave her alone and let her text me next?
2.) If not, what is a fun, non-needy way to re-engage her to keep interest in me peaked while not seeming to pushy or beta?
3.) Since we are not officially dating, just sort of hanging out and fucking on occasion, should I even be concerned?

I am new to this whole idea of text game and have been a beta in previous relationships but have pinpointed my sticking points and am trying to work them out. I have never had a problem attracting and banging a girl on the first or second date, but keeping them interested for a long term relationship has always been difficult for me. It's almost like the guy they banged transforms into some beta and it wreaks of incongruency. My gut is telling me to not text her at all and let her re-initiate but if she doesn't re-initiate, then I will feel like I lost and made the wrong call.

Sorry for the length of this post but I feel the more information the better the advice. Thanks for your help, fellas