supposed to maintain but still losing..

It is good to hear that over the past ~4 months you succeeded in increasing your calories to an average of 1500 to 1700 a day.

Your estimated sedentary maintenance level remains a bit higher that that, at 1830. You also have to account for the 60 minutes of elliptical x 6 times a week, plus your 20K, or so, steps a day.

20K steps a day, by themselves, constitute an activity level slightly higher than very active, as opposed to the sedentary level that 1830 represents.

To someone on the outside there is an obvious caloric gap and the solution is obvious:

--Stop exercising until you can increase your food intake sufficiently.
--Reduce your in-place walking and all other un-necessary activities until you can increase your food intake sufficiently.
--Ingest and absorb more calories (and use a trending weight application to monitor your weight level).

If large quantities of food present a problem for you, swap in full fat and real sugar options and swap out low fat and artificially sweetened "diet" options.

As mentioned by someone above, nuts and nut butters, pack a lot of calories in small packages.

Even though you are aware of these options, it appears that you have been only partially successful in implementing them these past few months.

To an outsider it becomes obvious that something inside you is holding you back.

Campus counselling, student health, your family doctor (or, if your family doctor is not an option, how about a doctor who is not known to the rest of your family and who you approach privately, on your own?) may all help get you started towards finding the additional help you may need to move forward.