If I remember correctly, this manga starts off with a girl transferring into the school and being really stand-offish. Doesn't' talk to anyone and tends to stay alone. One day, while the male MC was hiding out in a confession booth, the new girl comes in and confesses her sin of giving birth to a child and giving it away. The male MC is shocked to hear this and encourages the girl to not lose hope. Afterwards, he starts to try to get close to her and help her out on whatever she needs, even if she's uncomfortable with anyone touching her, so she can be happy.

If anyone can help me out on finding this manga, I'd be really grateful. Been meaning to recommend it, but it's kinda hard to do that when you can't remember what it's called.

Bitter Virgin

~4400 manga completed
~1700 ongoing...

Yes, thank you! Just seeing the name made it all come back to me.