(HUGS) hun.
4 months is a TOUGH time. First there is teething, developmental changes, increased mobility and along with all this comes a change i nthe ways babies sleep. They start to sleep more like we do and stir more in the night as they cycle in and out of sleep states. During this time they wake, and some can not put themselves back to sleep. It is something they are learning.
THis is the time that a lot of things such as dummies and the breast can become strong props.
All that aside, you are right, it looks like your LO is OT. We had a similar thing when DS was 4 months old and the 30min naps started. For us, W2S and HTTJ helped. Do you know what these methods are and how to use them? This could be a good way to get your LO caught up on lost sleep so that she can then get into a routine and if needed you can do some sleep training.
You also need to remember when they have short naps, their A times will decrease as they are not refreshed, the edge has just been taken off. I would reduce each A time after a short nap 20mins or even more (it all depends on the LO) but watch for those signs. It will mean you are putting her down more often, but she needs to catch up on that OT