9 months since Mum passed and really struggling

I lost mum 9 months ago after a very long and tough battle of different cancers for 10 year i cared for mum for nearly 7 year and she had a very rough last week with not being given the right pain meds after she asked them to make her comfortable I have a daily struggle but it's getting worse if I hear certain types of noise it takes me back to the hospital where she struggled to breath and it won't leave my head or a certain smell takes me back to the same place it haunts me daily and I can't get it out of my head no matter how hard I try