What is biting me when i sleep?

ok when i got to sleep i wake up andi have bites on my bady and they itch really badly so i looked around my bed and etc and seen no signs of bed bugs not even 1 so i am not sure what it is...and fyi other ppl have slept in my bed too while i was gone or just during the day to nap or what ever and they have not been bite can any one give me any advise on this....SN: my bf also sleeps with em and does not get bite