any tips on getting babies in a schedule

Kailyn
To sleep longer at night?! I love my daughter to no end and I would do anything for her but I am soooooo desperate for sleep!!! She's almost 3 months and she is waking up every 2 sometimes if I'm lucky 3 hours to eat and her pediatrician said she's at the point where now we can train her to eat every 4-5 hours at night and to just give her a pacifier at night in between if she wakes up... I tried it for two nights and I just felt so awful I ended up feeding her. I didn't want her to be hungry :( 
I kind of felt like those two nights of attempting to "train" her were worse and I got less than sleep ever. 
So now I don't know what to do. I'm just really exhausted. Being a single mom I don't have any help. Just me and baby. Anyone else expierence the same thing? 
Have any ideas for me ?? 
Someone please tell me it gets better and a good nights rest will be coming my way soon 😖😫 lol