milk supply (again)

I know I have posted about this earlier but it is an issue again. I think it may just be one of those weeks for me but I am now starting to have to dip into my supply more. For instance, today I had about 4 ozs of fresh milk for Nash. I had to give my mom a frozen bag too. I only pumped 1 and 1/2 oz at work the first time. I am down to pumping twice a day. I see formula being supplemented in the near future as I will be going through my frozen stash quicker. I have nothing against formula and am mighty proud of myself for making it 6 1/2 months probably 7 of pure breast milk (other than the couple of ozs of formula he gets in his cereal). I still plan on nursing him all the time when I am with him and just supplementing with formula when I am not. I have a feeling that the supply will be getting low though. Previously when Nash slept through the night or had a long stretch of sleep I would feel real full but not so much any more. What is crazy to me is that there is enough supply when I am with him but not when I'm not? How is that possible? I know that babies are able to get more milk from you than the pump does so that would make some sense. I have been wanting to see where an end to breastfeeding might be so this might be my answer. I think I am going to just go with it. The cons are in the middle of the night having to make a bottle and just having to make a bottle period. Also, Nash seems to prefer it but he is doing well with his bottle now without me (don't know how he would do with a bottle with me). The pros are not having to worry with it any more and being able to leave or go to work without pumping. I guess I am a little indifferent. I still enjoy the not having to mess with the bottles myself. So, I guess the plan is use up the rest of my frozen stash, still pump at work (even though it will be less than he needs) until I am completely ready to give it up, then I will cut back, supplement with formula when the stash runs out, continue to breastfeed when I'm with him, and then when I am getting ready to totally quit I will start cutting back on that too. Does that make sense? I seem to make things more complicated then they are. I think this is just a big issue for me because it is such a bond with me and Nash. On one hand, I really enjoy it and am glad to have done it. On the other hand, I don't want to do it forever and am wondering if I am getting the the crossroads. I didn't think I would make it this far and it is such an adjustment to stop it but one I will do gradually.