Hi Karina, thought I'd post because night-waking is always on my mind
I have always winged about Natalie's sleep patterns, and in hindsight, I had it soooo good until about 4 months. Then she started waking more frequently, say 3-5 times a night.
Here are some of my thoughts...
Firstly, I'm led to believe that often babies who sleep ok in their first months of life can become more wakeful at around 4 months. This leads me to think partly it is developmental, and certainly her pattern of night-waking has chopped and changed over this time, perhaps due to developments she was going through.
Secondly, you have my blessing to punch in the mouth anyone who seems incredulous at you feeding a 5 month old baby overnight. How utterly ridiculous. I'm told that 5-month-old babies who go to tresssillian residential sleep school still have a feed overnight. 5 months old is still very little. And I reckon people who say their baby slept through every night from their first night home from hospital are not being entirely truthful.
Thirdly, regarding associations with sleep and booby - definitely true IMO. Since I have stopped feeding Natalie to sleep, I think her sleeping pattern has improved. Her day sleeps tend to be longer if she self-settles, and I try to feed her at least 20mins before bedtime, and put her to bed awake to self-settle for the night. Sometimes she only goes for 2 hours, but sometimes she will go for 3.5-4 hours which is IMO great. (BTW, she didn't start to self-settle til about 5 months old, and only occasionally. It is only in the last couple of weeks that she'll self-settle for day sleeps more often than not. Before I used to pat her to sleep to settle her.) She will only settle with booby overnight tho. Part of me believes she is thirsty, but if I'm totally honest, I think she needs booby to get back to sleep. Not sure how to get through this...
Lastly, in regard to the day sleeping affecting night sleeping: I was a great sceptic! I had a thread not too long ago about this. However lately I have found it to be true to a point for us. If Natalie has two 2-2.5 hour sleeps in one day, she does tend to wake for a play in the night. However, if she has one 1 hour and one 2 hour sleep during the day, her night sleeping is as good as it gets. Today we were out most of the day, and she only had 10 mins this morning and 40 mins this afternoon She fell into bed at 6:30 (usual bedtime is 7) and woke up at 7:40, resettled herself after a minute or two, then woke for a feed (ie wouldn't settle herself) at 8:45. This is not particularly good for her, and I'm blaming it on the small amount of sleep she had today.
I know this is long-winded, and TBH probably more for my benefit than yours but know that you're not alone in having a wakeful baby. I'm lucky in that I am able to get to sleep easily after a night feed, so for me its a no-brainer. I just feed her. (I tried settling with cuddles for the first wake-up, which did work for a while, but no longer unfortunately.) For you, I can totally understand your frustration - having very little sleep overnight and not getting a decent nap out of her during the day in which to catch up on some zzz's yourself must be beyond exhausting. If I were in your position, sleep means that much to me that I would probably seek some help. Tressillian have a phone help-line and I have found them to be great on the two occasions I have phoned them. They have made some helpful suggestions.
Hoping you can find some resolution soon. Sleep deprivation sucks. All the best as you work it out.