It all counts, keep it up!

So, is it really 1.8 miles in 30 minutes? Like, 15 minutes there, lutz around for a couple minutes and then 15 minutes back? If so, you are going at a good clip. That is 3.6 miles an hour for walking which is considered brisk and on grass? Even better timing as that is more resistance ton the walking. Now, if it is taking 30 minutes for .9 miles, that is slow, but it's a starting point and nothing to be ashamed of as you are pushing yourself and doing the best you can.

I have a question too about my job. I put away books in a library I only work 3 days a week for 2 or 4 hours at a time but I wonder how many if any calories are burned

Even if you knew how many calories you burned, that's not something I would personally track. That's the course of your normal day - it's not "exercise". Does that make sense?

I joked a couple of weeks ago at the office, when I was heaving around heavy file boxes, moving large vertical file cabinets, and setting up storage shelves, "I better be earning activity points for this!!!". I didn't actually calculate or count them though.

I consider any extra daily activities to be bonus calories on my BMR. I don't count them as exercise. You have to have a very physical job to make a huge difference in your BMR. You will burn extra calories, just not a huge amount, maybe like 60-80 extra calories per hour.