For the first time I know what fear is, my physical strength cannot hold up anymore and I have to sleep, yet all that going through my head is all the possible

For the first time I know what fear is, my physical strength cannot hold up anymore and I have to sleep, yet all that going through my head is all the possible scenarios that could happen. Had a dream that everything turned out to be okay, woke up at 4am out of excitement, checked phone/messages, still no response. Then realize it was just a dream, and burst in tears again. Going through every corner on the internet to find the smallest trace that he's still okay.. for the first time when people asked me if everything's alright, i responded "no". I have no idea how I can possibly focus on work and normal life today without going through a mental breakdown.