Sleep training is changing their behaviour so they can sleep without you settling them or whatever.
Your dd sounds ripe forit . My dd was a nightmare for 6 months until we sorted her. We did this:
Go in, lie her back down pat her and say night night or whatever,no eye contact, walk straight out. Go straight back in, lie her back down, etc etc etc. She will cry, but she is never left to cry. Only stop going in when she stops crying. If she starts again, repeat until she calms down again.
We had to do this for 3 nights until her behaviour changed. After 2 weeks she was going through, and now sleeps much better in the day as well.
Believe me, no one could have been more desperate than me, I posted millions of pleas for help on here. We were having to sit with her, pat her etc all night, and then she would still be awake and screaming for about 2 or 3 hours every night.
The whole house was exhausted, and now life is great again Try not to give in, it takes abut 2 or 3 weeks to work, but she WILL respond HONESTLY! After months of sitting by her when she went to sleep, never daring to leave the room in case she started she now waves night night to use, and rolls over and goes to sleep
No horrible controlled crying or leaving her to cry, although as I said she will cry.
Am an absolute zealot about this method, it changed all our lives