In our bed so exhausted all the time now

Please help. We are at our wits end with this …..
My 8. Yr old cocker bitch is driving us crazy. She slept in the loung until she was about four. Then my hubby decided it was cruel because she scratched to come out in the middle of the night a few times. So she was allowed the run of the house. Downstairs and upstairs. She sleeps part of the night on our spare bed in the spare bedroom. But I’m thinking she gets cold because at some time between 2am and 6am she leaps onto our bed not caring where she lands and pushes her way under our duvet. She takes up the whole bed and after about an hour she decided to clean herself and toodle back to the spare room. This happens every single night. I feel like we have a baby again. I feel wretched in the mornings as I e had broken sleep at least twice in the night. I’m stiff too as I’m squashed whilst she’s stretching out.
Should I get a stair gate and persevere with making her stay downstairs again. I won’t shut any doors but just stop her getting up the stairs. I know I’m in for some sleepless nights but does anyone think it will work and we can go back to normal sleeping again?
Any tips would be greatly received. Thanks in advance.