My best friend read my message and didnt reply, it was something important?

Anything that appears to be somewhat life-threatening or is bothersome enough to warrant an asap, shouldn't you have rung the person or at best gone round to see them? However, your interpretation of the friendships is yours and yours alone as she gaged/judged your actions as to what really is an asap and sadly you appear to be a clingy friend that she appears to solely tolerate as opposed to placing you high on her agender when it comes to one of your cry wolf dramas! As for what to make of it, or even what to say, I'd think before blindly losing your rag and possibly the only friend that is prepared to listen to your whinging that's frequent, hence, her being your only ally as you tend to overreact way too often, so be warned? Why? Because you could very well lose the only ally you have due to your clingy dramatical nature at attempting to ask for support!