Hugs to you as it's tough. I can't offer much advice as I'm more in the sleep training camp and can't cope personally with co sleeping, constant feeding etc but I just wanted to say don't feel guilty or feel it's your fault. I started trying to get ds2 to self settle at about 8 weeks and he was doing well. Then he hit the 4 month sleep regression and would wake every 45 mins or so and I took the attitude of doing whatever worked to get him back to sleep which ended up being feeding. I kept thinking it would be ok as I would do some sleep training at 6 months like I did with ds1 and it would all be fine. Well 2 months down the line of sleep training and he's still a monster! I spent the first few weeks thinking it was all my fault, I had got him into bad habits etc but I've come to realise that all babies are unique and my little one is just never going to be a great sleeper. He's more needy and although we worked hard to get his sleep better (was down to 2 night wakings) he's the kind of baby that gets disrupted easily so now he has a cold and was waking literally every 10-15 mins a few nights ago.
If you are happy with the suggestions offered such as co sleeping I would just do what you can to get through, don't worry that you are setting up bad habits as it just causes unnecessary stress. And also don't feel bad that you are struggling. I think it can be very hard hearing people say "oh mine were the same, I just did this and that and it worked fine." Well sadly some things don't work for all of us, I can't co sleep or feed lying down so it's never helped me with constant wakings and I've felt that my desire to get baby sleeping better (and me!) has been a selfish decision as other people just go with the flow and manage fine. Do what you need to get through this tough stage. Good luck.