It is great to see you reaching out here on the forum. Your feelings are real and the situation is so tough at the moment. I am sorry that you are separated from your partner, this would feel so isolating and it would be difficult to be at home and see the little families around you. Being long distance is hard enough at the best of times, never mind when it is forced. We are all facing incredibly big and fast changes with so much information to process in our minds. It takes a lot of our mental energy from being able to focus on the tasks at hand and concentrate. This is a really normal response. The people with children working at home have new distractions with kids running around in the background, and that can be distracting for everyone. A friend of mine says she is at home working with kids and has no time to think and have a break. In your case, it sounds like you have too much time to think about the unknown and the 'what it's'. The situation is not ideal for anyone and is a massive adjustment.
Be kind to yourself during this time.
During this type of experience, it is important to balance your focus on things that are within your realm of control. Sometimes making a list can help. For example, you can control the amount of media your view, you could write letters to your partner, use video catch ups and schedule these with your friends and family or take an online fitness class (there are many popping up) or learn to cook a new dish. Putting some structure to your days can really help and creating a weekly schedule with activities and things you aim to achieve can help focus and keep you active, even within your own space.
People are changing (rapidly) how they do things and adjusting to creating new opportunities for virtual connection. There are virtual museums to explore and you might take a trip on YouTube to a place you have always wanted to visit.
The unknown is scary at the moment for all of us, but we can still put our feet on the ground and be in the here and now. Tomorrow is a new day and you might have a really positive experience at the grocery store. I saw a guy today grab some toilet paper (it was the last batch) and a young woman came walking down who looked disappointed she didn't get any, and he just gave her his pack. It was nice.
Another good thread to look at on the forum is the 'Coping with Coronavirus outbreak' where there are lots of strategies being shared.