Feeling the failure

Today is one of those days that I feel like I am just failing and not actually moving forward.  I did try to get on the bike but after 5 mins wanted to puke and was light headed.  Most would say no biggie just stop and try again tomorrow.   But tonight I just feel like I am making excuses.  I want to be healthier and more in shape and yet can't get my but moving or have enough self discipline to stick to eating healthy.  I make one excuse after another.  I know these things take time.  I guess I want to be like all of those success stories that just one day I woke up and wasn't going to take it anymore.  That I would never have a set back again and only results.... But that isn't realistic with three kids and having just moved to a totally new climate and well there are the excuses again.  It's not like I don't want it,  I guess I just don't want it enough... I don't know what is wrong with me.