Cuchulan is right on the mark. Experiencing a loss of any kind can create a whole new line of anxiety. Everyone deals with it differently. Some need to talk about it. Some feel better writing it down. Some need to bury themselves in a hobby or work. You may need to try a few different things until something starts helping. It's also painful in a way that other anxiety may not be. But you will heal and so will your boyfriend. It just takes time. Also, it can help to write down or talk about the good memories. Life is a celebration of our spirit and how we touched others.
I can relate to mounting anxiety from all those triggers, as well. I felt this when I was finishing college. I had more than a full courseload, interned, worked part-time, was engaged, and so on. And then when I was getting a divorce about 6 years later, I had 2 sons (under age 4) to take care of and worry about, a house to sell, going back to work after being a stay-at home dad for 3 years, and so on.
What are you are feeling is normal given all the events filling your life right now. It's just more intense when you suffer from anxiety. My mom used to say it was just worrying, but I realized later that it was so much more. Try to focus on positive things in your life and develop what I like to call a "mental emergency kit". Make a list of things that you can do, people you can see, or places you can go nearby that make you feel happy. When you start to feel overwhelmed, refer to your emergency kit to help you keep yourself from reeling. It's hard at first and sounds silly. But finding and reminding yourself of "good things" in the world can help you to heal.
Most important, don't be afraid to ask for help. There is always someone that can be there for you. Even on this site. Take care and hope things start to get better for you.