23 weeks and so dizzy!!

For over a week now I have been waking up everyday feeling dizzy and with a pounding headache, the headache does go away on its own or with paracetamol but the dizziness remains all day and I constantly just feel off balance. My vision keeps going blurry too and I find it so difficult to do normal day to day tasks like tidying and washing etc. I'm also struggling to look after my 1 year old daughter! I've been to the hospital twice last week and they checked my bloods and all was fine, they also checked my blood pressure and that's all fine too. They have told me they think it's just pregnancy related and that I should just drink plenty of fluids and rest as much as possible. Of course it sets my anxiety into overdrive and I have spent that past 3 days crying because it's so scary. Is anyone else experiencing the same thing? I never really had this problem when I was pregnant with my daughter.