Feeling too overprotective?

Lately since my babygirl has been pregnant i've been stressing out so much, watching her jump and land so carelessly. I won't let her go outside, because I fear she'll have her kittens outside, or if she has any complications and needs my help, I won't know where she is.  My mom thinks we should let her go outside and she's saying im smothering her, but I feel like Im just helping her. I fill her food and water bowls constantly. If any other animals go in her nesting spot I wash all the blankets, I can't even go out without feeling like I need to be there for her.  

Am I being too over protective, or am I just properly caring for my cat and her future babies.

P.s she's almost due now, so that's why Im taking extra extra care of her.

You need to keep her in until she is spayed.  Ask your vets how soon after delivery that can be done.  Cats are quite capable of getting pregnant whilst nursing kittens.  And she will probably need a room of her own, away from the other 'animals' (cats?  dogs?) when she has small kittens.  Cats are usually very protective of their kittens and won't hesistate to attack any animal they perceive as a threat.

Do you have a set of digital scales that weigh in grams?  If not look for a cheap pair - $15 or less.  Once the kittens have arrived weigh the kittens at about the same time each day and record the results - I used a spreadsheet.  They should each be gaining 10g or more most days.  Grams are good to use for this as 10 is a nice easy number to remember, and there are no decimal points or fractions to deal with.  If you use ounces that is what you have to cope with.

You're doing right to keep her in close to delivery so she doesn't end up having the kittens somewhere outside that you can't find them or they get killed by a predator.

and Shunra is right that you also have to then keep her in until she can be spayed.   Cats can get pregnant even if they are nursing young kittens.  but it's not good for them or the kittens if that happens!  

Re scales If you use a scale that weighs in ounces,   you want to see them put on  1/3 ounce a day   better yet is 1/2 ounce.  

1/3 ounce -  10 grams.  1/2 ounce  -- 15 grams.