Like the previous respondent said, there are many techniques like those she mentioned which has helped many mothers. HOWEVER, yes, every baby/child is different. Not all babies will react to these methods perfectly. Remember, at this age, 5 months, they are going through LOTS of developmental changes, cognitive changes, and everything else. At these time, and during growth spurts, they may be more hungry, and their sleep patterns CHANGE. Sleep patterns in babies/children are NOT static...they WILL change and they change and develop. I am in a similar situation... my son is 17 months, and my daughter is 5. When my son was brand new... I was getting up all night with him, and my daughter during the night. Yes, it's tiring. But it will pass. Take heart. In my son's and daughter's case, their sleep patterns changed about this age at well and around 6 months old. They also will develop "separation" feelings, and my Pediatrician said they may get up more as they are more "aware" of their surroundings, AND they want to "see" where Mommy is etc. For my son, he slept through the night since birth, THEN at about 6 months old, he changed and started to wake up twice a night. He could get himself back to sleep, (I would just let him babble to himself...and didn't interfere, and he'd get himself back to sleep). Other times, he would wake up, and cry and cry. It was then that he was actually hungry, and he'd need a bottle, he'd drink it ALL in one sitting, then go right back to sleep. Now at his age of 17 months, he still wakes sometimes in the middle of the night, but it's only for a brief second. I do NOT swoop in right away, unless he's having "night terrors" or something. At this age, they get "nightmares" and dream... and it can wake them up. Each child IS different. It's just something we have to do. For my son, he likes to use a pacifier to sleep, and he has a stuffed cow that he really loves to cuddle as he sleeps. This is his "transition" object and it helps him to sleep. It's his "routine" and this is important in their sleep habits. I know lack of sleep right now is hard... I've had lack of sleep for the past 5 years! LOL! Yes, my first child, my daughter was a very LIGHT sleeper and anything would wake her up. It was only until she was 4, that she actually slept through the night, even if there were "noises" in the house. Then my son was born and I was right back to "no sleep" and getting up during the night again. No rest or break for Mommy! LOL! But.. well, it will pass, and before you know it, they will no longer be babies... so it's okay. Just rest when you can, or have hubby take the kids out or entertain them on the weekends or evenings so you can rest and have a break. That's what we do. But I know it's not always possible. You are not alone... take care and you will get a lot of opinions here. Hope it helps.
By the way, feeding "solids" is typically started at 6 months... or per your Pediatricians recommendations.
~Susan
www.cafepress.com/littlegoogoo