am I emotionally hurting my kid?

My LO is 4 months old today. He has been fussy and irritable lately and we have been coping by having him hang out in his kinderpack most of the time. Last night..as in a few hours ago he would not go to bed. Usually I can feed him and slip him into his co-sleeper no problem. Well he would fall asleep nursing then immediately start crying every time I put him down. So to avoid totally freaking out I put him in his own room...first time ever.. and shut the door. I let him fuss for 5 minutes then went in to pat him and talk to him. Then waited 5 more minutes and went to pat him again. Within 25 minutes he was asleep. He slept from 9:00p-1am. He started fussing at 1, again I let him fuss he was back to sleep within 3 minutes. I don't know much about cry it out or any other methods of sleep training..im just trying to do what works for us. Does it sound like we're doing ok?