New ducky owner:)

Hello- I just joined this forum because for the past week, I have been referring to it to answer my questions about my 2 week old ducks. I went to Tractor Supply the week before Easter and could not bear to leave without 2 ducklings. It was a surprise for my parents when I came home from college the next day with 2 Pekins. Thankfully, they were still cute enough to smooth everything over. I live on a farm with a creek so I knew once they were older, we could let them roam on our property. I figured I would just leave them at home so they could get acquainted with the place but my dad informed me they were my responsibility until they were old enough to live outside on their own. He agreed to build a little duck house for them and to have it ready for when I next came home with them.
This past week, I noticed one of the ducks' legs was bowing a little bit. A friend of mine informed me that it was probably just a torn ligament so I rubbed it off. The next morning, I let both of the ducks swim while I cleaned their cage (a dog kennel in my apt. bathroom). When I took them both out of the tub, I noticed one of them kept falling over. It kept trying to "itch" its chest but he couldn't stabilize his body. I picked him and noticed he wouldn't stop moving his legs. It was as if he was swimming in mid-air. It was 5 min from that point that he could no longer walk at all. Keep in mind that this week is finals week for me and I am a senior in college so it's a tough week. I knew I had to study that whole day but I threw clothes on, grabbed the duck and went to the closest vet. The first thing they told me was that he was burning up. I figured it was because his legs hadn't stopped moving for the past 30 minutes. The doctor finally called me back and informed me it wasn't good. He figured that the duck had somehow bumped his head and his balance was affected. His respiratory system was already shutting down by the time I made it to the room. I lost all emotion. I had no idea how much I had grown to love this duck! I cried and cried and cried with that doctor, and I felt like a fool, but thankfully, he was so understanding. He suggested to go ahead and put him down. I said goodbye and cried the rest of the day. It was AWFUL! I came home to my other duckling and held it and just cried and cried some more. Since then, I've made sure to stay at home and let the other one just roam free around my apartment since "she" doesn't have a friend anymore. Because of this, "she" follows me everywhere. I even had to put the kennel next to my bed last night so she knew I was right there and she wasn't alone. It's breaking my heart that she doesn't have a friend, but my dad still isn't fond of the whole duck thing. I am not sure whether to get another duck or not. I am going home for a 4 days and then coming back to my college town for the following 3 weeks. I think she will be too big to keep her here for much longer. I'm stuck! I don't know if we should just attempt her to roam on her own on our property, or just wait it out and see if we end up getting another duckling. I've grown to love this little duck even more because having the other one gone made me realize how much I care for these little guys. This is all a learning process for me, but any advice on ANYTHING is so appreciated! I know I have written a book! Sorry about that! But really, please feel free to inform me on any suggestions for my current situation! Thanks so much!