Sit down and really look at your relationship with them.
Is "driving them places and giving them money" really all there is to it?
Do you:
Volunteer at their school(s)? At their activities? Are you active with events at school, are you a parent who helps organize soccer/chess/Scouts/church groups/whatever it is they do outside school? If not: Get involved. The schools need you. There are SO many ways to do it -- look at what your PTA offers (many have after-school classes in arts, dance, chess club, "mad science" fun classes, etc. you name it --and if your school offers nothing, be the one to get something organized!). If you go to a church or synagogue or other place of worship, what can you do there? Outside your kids' world, what volunteering would interest you -- working with a food bank to sort and distribute food? Working to teach basic literacy skills to those who don't have any? Working with the local hospital or Red Cross on blood drives? MANY places need your help right now and you can't use the excuse "I don't have any experience" -- volunteers do not need experience!
You may be missing huge opportunities to be much more involved in your kids' lives. The "they don't need me" only means they don't need to be fed by hand and dressed any more. They DO need you to show an interest in what interests them, and to get involved. They do need you to demonstrate an interest in the larger world too, by having your own activities that don't depend on them.
You have so much to offer and it's not "shopping and hanging out to talk about boys" -- that's not what we SAHMs whose kids are in school do all day (though a little shopping is always a welcome distraction!).
The best way out of your funk is to help others, both to help your own kids by being involved in their schools and activities, and to help the rest of the world by being involved in whatever cause interests YOU.
If you really do feel your kids have little to do with you other than asking for money and rides -- they're way young for things to be at that stage already. Things are not about either "the teen years or toddlerhood" as you call it; your kids are currently in the wonderful elementary years and they need you MORE than ever, not less. They need to navigate social relationships, figure out who they are, deal with good friends and possibly some bullies, learn to work with teachers they may not like but must listen to, learn how to study...Do you see that they need you now? In ways more important than "taking care of them" as you did when they were little and their needs were so simple?
Get to know the people they are now, the needs they have now (which are greater than you realize) and get involved. Babyhood and preschool are fine but you're in some great and potentially tough years when they need your full attention and more, not less, involvement.