My mum is so Over protective!?

Me and my mum are best friends and i love her too bits! but she is very over protective!! I have a great relationship with her, we get on like a house on fire but ever since i have been going out with my boyfriend (1 year and 4 months), she has became very jealous and always holding grudges against me and my boyfriend. We have had but protected and always be careful, and of the legal age. My mum and dad are still together and my dad says its because she is scared she is gonna loose her wee girl. I am going on holiday with my boyfriend and she wont even let me share a bed with him, but maybe thats me being selfish and huffing cause i am not getting own way. She used to get on with my boyfriend then shestarted telling me that he wasnt the one for me, then she apologises and she hasnt been nasty about him in a while. I just want her too trust me but when i talk about the holiday she gets all wound up and it irritates me soo much. what do i say to her? Help!!!!!!!!