Help me - so tired

My daughter is 4.5 months old. Since 3 months old, we’ve been trying to sleep train her by putting her drowsy but awake in the crib. It doesn’t work all the time but we’ve had some success. However, she’s been waking up and not being able to be resettled for TWO HOURS every night. I tried feeding her to sleep and even that doesn’t work anymore. Mamas, can you please help??? Why is this happening? Is she not getting calories during the day? She takes three naps a day (in total 2-3 hours) and goes to bed at 7pm.