Will taking two zyrtec help dry up fluid in the eustachian tube faster? or would it just make it worse?

Neither: fluid in the middle ear can be due to several reasons, infection is one of them, whether viral or bacterial, Eustachian tube dysfunction is another, so relieving the congestion by whatever means is the mainstay in therapy, antihistamines do little in relieving congestion. Saline nasal washes, salt water gargles, steroid nasal sprays, antibiotics, if needed, may help,your doctor would judge better