Is it normal to have random short periods of anxiety/small hyperventilating months after fiance passed away? Sometimes I'll just be doing things about my day and I'll just randomly think of her and be hit with the feeling of anxiety in my chest, the feeling of powerlessness, and faintly hyper-ventilate in the way it felt like the night of her accident.

It's been 4 months, and during the first 4 months of grief I've been in tears, but I've been keeping it together for the most part after the first 2 months and doing my best to keep moving on with life. This random feeling I've been getting is new, and sometimes it makes me cry spontaneously. 

It doesn't feel right or normal, but I don't know if it is because no one I know has dealt with grief like this, so I have no one to ask. Is this a normal part of grief?