So glad to see how well you're doing.
The day sleep problems could be from being overtired. Do you use a sling/carrier at all? they can be life savers during the daytimes.
DS also cluster fed between 4-7pm, roughly every 45-60mins or so, and was just generally very fussy at that time. I think he stopped doing that around 3.5-4months or so.
Like Jen said, if you feed him the milk will come. Your bbs feel softer cause you're emptying them more often, which actually means you're making more milk (you make more the emptier they are) - it just doesn't seem like it.