Crib training?

Julia

My son is 4 months old. Since he was 10 days old he has slept in a bassinet next to my bed. He was only 4 lbs when we brought him home so I didn't feel comfortable with him in his crib. But he's getting way too big for it. I can get him to sleep in his crib but he will only sleep for maybe 20-25 minute then wakes up crying. Should I just let him cry? I feel so bad doing that 😔 I've never just let him cry before.