Why isn't she sleeping???

We had been doing really good, or I say WE I mean PAYTON. She was sleeping through the night so I thought everything was good with night time sleep. I think I will always have a battle with the naps. But I told myself that was fine, I could deal with little naps as long as she slept through the night. Well- the past 5 days or so she has been waking up a lot through the night. When you get woke up in the night and you are so tired (I am so tired) then my first thought is to go get a bottle and go and feed her. But then as I am sitting there rocking and feeding her in the middle of the night I am like "why did I make her this bottle? Is she really hungry? Does she just "think" she needs this?" Since I know she is capable of sleeping through the night it makes it that much tougher for me to decide what to do?

Her cry is not just a little whine cry like "I am tired and about to fall back asleep cry" It is the "help me cry I am hurting...." (She isn't really hurting, it just sounds like that.)

So after many nights of this going on and waking up every 3 hours. I went in and still fed her at midnight. I then remembered that I HAD been laying her down wide awake after her bottle and she put herself to sleep. Well- about a week ago she cried one night so I rocked he to sleep. I guess I have been continuing to rock her and not "just lay her down". So I started thinking is this the problem??? So after the bottle at midnight, I decided to just lay her down. Well she started to scream. I let her cry for about 20 minutes. Well I can't sleep because even with the monitor off I can still hear my baby crying. I don't like to hear that, at all. So I go back in there, try to rock her, she continues to cry while I am holding her (which usually does not happen) but I guess she got herself so upset she couldn't calm down. So I thought well if you are going to cry while I hold you then I will just lay you down and let you cry. (Mean mommy, I know) Well she cried harder...... So I go back in there, rock her SOUND to sleep, lay her down asleep, walk out and she begins to make little cries but nothing too bad then stayed asleep for almost 4 hours.

Why is this happening? Has anyone else had this issue with their baby?? I thought could it be teething? But I really do not think so.