Oh hun, I KNOW what it feels like.
DD slept like a dream the first 4 months or so. Well, she woke a couple of times a night, but that's normal. But then she reverted to feeding lots and lots during the night, sometimes only sleeping with a nipple in her mouth ALL BLOODY NIGHT!
DS is doing the exact same thing. Although he's not quite as booby-addicted and just needs a quick cuddle or wants to sleep on my chest for a little while.
I think most babies go through a phase like that. Some even go through it a couple of times.
at this age, your baby is probably getting a whole lot more mobile. Practicing rolling or maybe even crawling at night makes for disturbed sleep.

Try not to focus on how little sleep you are getting. Go with the flow. I personally found that whenever I tried to actively improve the situation, I got really frustrated and then my frustration seemed to make everything so much worse. When I relaxed about it and just tried to work with it, things seemed to improve.
My children slept in my bed full time for the first few months. Then in a cot next to my bed. On unsettled nights, DS sleeps with me. This way I can maximise the amount of sleep I'm getting. This is not for everyone, but works for me. Of course it is still interrupted sleep, but better than nothing. I'm also someone who needs a relatively large amount of sleep to function well. But with a baby and a toddler, sleeping during the day is not usually an option. So I really do understand how this can get to you. I used to have a deal with DH that one day of the weekend was my sleep-in morning. He'd take DD into the yard or to the park to play, give her breakfast etc and I got to sleep in. Well, that was before we had DS...

It really is only a phase. Just repeat after me: This too shall pass. This too shall pass.

If you need a more active approach, you could enlist DH to give him a bottle of EBM for one or two of the night feedings. A couple of times, when I was very fatigued, after a particularly sleepless week, I had a deal with DH for one night that I'd deal with all wakings til 4am, the wakings after 4am where his job.

I hope you can get some rest!