Why did he visit me in a dream?

I had a dream about my mums father who is deceased.and who i never met in my dream i was at my dads house and i herd him saying john is coming over and i knew it was my mums dad. i thought OH crap and when he arrived he brought 3 Lady's and 2 men with him. i did my best to avoid him then he came up to me and i shook his hand and said in an angry voice i have herd alot about you!! and he said wow you really look like your mum. then i went to my room to get my mobile and i was just about in my room when he come running up behind me saying have u got 2 Min's come one while pushing and nudging me into my room i said no go away. and i fel on my bed and grabed the sheet and threw it over his head and ran into the kitchen thinking now i know how mum felt. it felt so real i woke up with a headache and told mum about it and she said yep that sounds like him. and i looked at a photo of him and he looked exactly the same in my dream squinty eyes fat and big with grey hair yuck... all day i had a headache and felt a negative feeling around me like he was following me all day was that him in spirit coming into my dream?