Desperate for sleep!

I had my third baby 4 months ago. I have no experience with sleep training. I’m a single mom and running on this little of sleep for the last 4 months is quite literally draining me. It’s impossible to function on such little sleep when I’m doing this alone 24/7.

I’ve never been the biggest fan of sleep training before 6 months but I’m desperate. Is 4 months too young? She’s hit the regression last week and it’s terrible. I’m talking waking up and wanting to eat every 20 minutes and most of the time, she won’t even go back down, she just screams. I have her on a pretty good bedtime routine, but I need to stop swaddling too, unsure if I should quit the swaddling first or do this all at once. What methods are the best for this age and are they even successful, or am I better off waiting a few more months? I’m clueless.