Dizziness

Is there anything to help with dizziness? I'm 20+2 with twins and it's interfering with everyday life. I can barely get up to make myself a drink and look after my 2 year old daughter. I feel bad as I want to do things around the house and play with her and do the normal day to day stuff. There's been a few times where I've felt the ground come towards me and I've caught myself and the only advice my midwife gave was to make sure I tried to fall against something soft! Thanks in advance.