How do I get my 2yr old to stop wanting to nurse?He won't drink cows milk,soy,ect.I too feel guilty to stop.?

I feel like i cant stop with out a good calcium alternative.i really enjoyed nursing & the bond we share,i wanted to stop by 1yr/1 1/2yrs old, but i have felt too guilty because he really won't drink any other milk.we have tried every cup,bottle, & trick in the book. he will drink the gerber yogurt mixed juices but i'm not sure that is a good enough alternative.Also he will not nap at home in the afternoon unless we are laying down together and he is nursing, so he will be cranky all day every day with out a nap.that is the only time we nurse in fact, once a day. sometimes if we have busy days we do skip a day or two completely. he'll sleep in the car or on very rare days he'll fall asleep randomly in our arms.so we are down to once a day /5 times a week, he only nurses on the left , which means the right one is practically back to normal, but i am lopsided, which is awful, i don't know how to take the final step with out sacrificing all of our sanity, rest, and possibly my little guys calcium needs.All the pros seem to know how to keep nursing but not so much how to stop my stubborn little guy.he's been this way since we tried to introduce bottles at 5months.(Fyi:my other son was nursed and we had him weaned to a bottle with milk and formula by 5months, no problems at all) i'm all about women making their own choices as far as how long they're comfortable nursing, but i really wanted to stop at least 9 months ago. i feel a little trapped.what do i do?