Edit: No memory.

If you are to remember the day, it does have an effect. So what you would do is request the designs for technology that would give you anything you want, remember those plans, and rebuild.

If I did not remember it I would just enjoy the day, as nothing will have changed afterwards.

It's really a hypothetical question. The situation I described doesn't have to be logical. Just assume it's true for the sake of answering the question. The dilemma is deciding whether to continue the day, not trying to find loopholes or logic flaws.

The existence of loopholes is essential to the answer I would give. It's not interesting at all to just say one's instant reaction and leave the thread.

The experiences only matter in the moment; it's the memory that truly matters most as it is what we remember our life by.

Without memories (and especially without consequences), nothing we do matters. It's why I find Alzheimer to be such a sad disease.

Hypothetically speaking, assuming there would be no loopholes...what will be your response?

Yes. 

I don't regard future me as the same person as me.

I would just continue the day since I would have nothing to lose and it literally wouldn't matter either way.

Though, knowing me, I'd probably waste it eating cheesecake all day. That "everything goes back to the way it was" part is good so I won't gain any weight :p

...Something I just thought of is whether the day is subtracted from your lifetime or not. If the day had the even tiniest cost, I would terminate it immediately.

What if I wrote down all the things I did or took pictures of me doing them, so that I would know what I did after I did them? That could work.