Dealing with grief

I lost my 17 year old dog Tyson on Wednesday. He was diagnosed with Lymphoma in early February and unfortunately his time was cut even shorter when he got pneumonia and passed on Wednesday 4th of March. I’ve had him since he was a puppy. He’s always been my side through everything. I really don’t know how to go on without him. This pain is unbearable and I’m not functioning very well at all. I’m probably just looking for some guidance on how to navigate this awful time.