Yearning, how do you expect to learn to do it for yourself if no one shows you? We are supposed to be taught it by our primary caregiver, and when we don't get it, it leaves a tremendous ache.
Actually by getting that need filled within the boundaries of the therapeutic relationship you will need eventually need it less, not more, you will become more independent not less. Yes you are 18 and technically an adult but that doesn't mean all of a sudden you are a fully fledged independent well functioning adult. It just doesn't work like that. Adulthood doesn't come all at once, it comes in lots of little steps forward. Your brain doesn't even stop maturing until you're 25. Becoming an adult is a great and scary adventure and everyone needs support and even when you get to 80 years old, you will still need people to care, you will still be dependent on others to a certain degree.

I can understand your therapist not wanting to nurture an over-dependence and that would look like you not dealing with things for yourself and constantly looking to her to put out minor fires etc. She has a responsibility to ensure you achieve emotion independence from her eventually. But Dependency and care are two totally different things. She seems to be withholding personalised care in an effort to make you " independent" Maybe she's trying to discourage maternal transference, i don't know.

All i know is you shouldn't be denied your feelings, or feel shamed for a very natural part of your own development. You need to be supported thru this, be allowed to be curious about your feelings and the need to grieve for what your mom didn't give you. And sometimes in therapy, therapist do become mother figures in absence of the real thing, and when i say that i don't mean someone to come tuck you in bed at night, i mean, they give you guidance, unconditional positive regard, empathy, sometimes advice if appropriate, they give you a safe place to return to when the real world is too much. And sometimes you will cling to them a bit but that is just one phase of therapy and eventually you will need her less and less. I don't know if this therapist can offer that and i think that's what you need to find out, because i think that is what you need.