... it is perfectly normal. Sure, she is weaning (and weaning is a process...not a slam dunk one time event), AND she is 2 years old.
I nursed both my kids until they self-weaned. My girl self-weaned at about 2.5 years old. Each child is different.
At this age, a child goes through TONS of changes- physically, emotionally, psychologically, developmentally. These changes are difficult for the Parent (hence we Moms ask questions)...BUT IT IS ALSO a difficult time for a child too. The child is the one being directly affected by all these changes...
Also at this age, YES... they develop 'fears' and fears of the dark. THIS is normal as well. They also have nightmares at this age too. It's all about ages and stages and development. My girl is 5 almost 6 years old.. .and at this age too, she still gets afraid of the dark. Her friends are the same way.
I would comfort your daughter....and not rebuff her. Sure, you don't have to nurse her again (maybe give her a sippy cup)....but it is a phase. Children, DO regress from time to time... this also is 'normal.' At times, it is in response to 'stress' or other changes in their lives. It is a "COPING" behavior.... this is what children do... they too need to learn coping skills and know that Mommy is there for them. I would NOT treat it as a control "problem."
If a child "feels" that their life is amicable, secure, and 'happy'... then they are more prone to adjusting easier and feeling that they can "trust" the situation. Your girl is going through a transition in her life.... and transitions take time- sometimes a week, sometimes weeks, sometimes months. Each child is different.
No child is going to sleep the entire night perfectly....every night. We need to "allow" for the occasional restless nights too. I don't know of anyone, or any Adults for that matter, who has slept ALL NIGHT, every night, for their entire life. We all wake up from time to time or have trouble sleeping. If this privilege is "allowed" for Adults... then we need to reflect on that toward our child as well.
Maybe offer her some kind of "lovey." A stuffed animal or something cozy she can have when she sleeps. Both my children did that and my son still loves his stuffed cow. It's his pal. Also, my girl likes to sleep with a flashlight in her bed... and all her stuffed animals. For her, it's comforting. Maybe try to find an alternative thing for your child to soothe & comfort with?
Eventually though... she WILL wean from nap-time nursings as well. You can choose to let her self-wean or not, it's up to you.
Some Mom's tell their child that when the sun goes down, Mommy's boobies go to sleep. (ie: no more milk). Then give her an alternative... a sippy cup of water or something.
Maybe there are other things too? Maybe she is getting in more teeth? Or having night-mares? This also occurs at this age too.
I think your girl is just going through more than 1 thing right now, not just the weaning. That's my guess. She is going through a lot of transitions and developmental changes right now.
Just try to comfort her, in a way that you feel best. There is no right or wrong answer. Except I would not "punish" her for it... or make her cry it out. Talk with her.. .kids need to feel validated too, and understood.
All the best,
Susan