Dealing with death.

Hi, first time poster, i want to know how everybody deals with death. I've never experienced death before and the thought of it terrifies me, I often depersonalise daily and wonder the point in life and why and what happens after death? Where do you go? After my therapy was done, these thoughts weren't as frequent but recently I've "let myself go" a little. Today I was in work when I received a text saying the dog I've had since I can remember as a child had died while I was working (I'm 18 for clarification and I've had this dog since I was 4/5). And in work, I felt nothing. I felt empty and hollow and then all of a sudden I was distracted, back to normal. But when my mind got a rest, I couldn't stop thinking about how if I wasn't in such a rush this morning to leave my house I could've said goodbye like I always do every morning. I missed my last chance to say goodbye. I've let myself and my dog down. I know this may not seem serious to some but this is the first death I've ever been close to and as soon as my mum picked me up, I felt so awkward. I could tell she was really upset but didn't know what to say, I didn't know whether I should say anything, so I didn't. I asked if she was ok. When I got home and saw my dogs bed, I ran downstairs and cried. I don't know what to do. How can I face my mum and her spot when I know she's not here anymore? I'll never see her again, I missed my chance.

My anxiety is killing me. I wanna know how anybody else copes?

Thank you,

Jacques