A.J.
Check out this site:
https://www.babysleepsite.com/how-we-sleep/4-month-old-sl...
It helped me ALOT with both kids. My second was similar to yours, he slept 12 hours at 2-3 months and around 4 months started waking every couple hours for me to either give a paci or nurse. The site talks about why this happens at this age and some things you can do about it. The #1 reason is usually because the child has a sleep association, meaning they are rocked or nursed to sleep, and she wants you to continue that all night...it's best to lay her in crib while tired but still awake. They also offer sleep consulatations (for $$), but have tons of FREE articles in there about baby sleep and naps. At 5 months they are typically old enough to start gentle sleep training IF there are no other medical issues, such as teething or illness. Another big issue is the napping...if baby is skipping naps they become too overtired and it actually makes it harder for them to stay asleep at night. Don't let baby be awake for more than 2 hour stretches at this age. Make first nap exactly or less than 2 hours after she first wakes up.
When getting ready for bed (probably around 7 or so) I would nurse her (or give a bottle) as much as she would eat, but make sure to remove breast or bottle BEFORE she falls completely asleep. Then continue to rock or sing for a bit until her eyes close (but not quite asleep). Then lay her in her crib gently, hold your arms around her for a minute then gently let go, maybe even rub her back for a minute or two, then gently walk out of the room. Then next part is up to you because at this point she may cry. If she does, if you are comfortable letting her cry (which is OK at this age) then I would do it. BUT make a plan to stick to it, because if you go back on it you will just confuse her and make it worse. Otherwise if you don't want her to CIO, just continue to rub back and soothe her, just until she almost falls asleep, then try to leave again, see what happens and repeat. If you do choose to let her cry then give it a good 10 minutes, and IF she is still crying, go in and rub her back, then leave again and next time don't go in until 15 minutes.
With my daughter this literally took 9 minutes and she never cried again. With my son, it took a little more persistance but was much better within a week. So you never know what you are going to get. At 5 months, they are still growing though, so I don't think 2 feedings a night is out of line, but when they go back to waking every hour it is SO FRUSTRATING and I feel for you. Sometimes it helps too, to not only give a good feeding before they goto bed, but then feed her before YOU goto bed as well. Then with any luck she will only wake around 4-5 AM and go back down.
Sorry this is so long, but hope it's somewhat helpful. I've never understood how other people's children just sleep though the night because I didn't luck out with either of mine, and read a TON of books because I was desparate for some shut-eye! Good luck momma and hang in there, I'm sure you know that it DOES get better (it's just hard to see when you're so damn tired!!)