Hi, and thanks for your medical question on eHealth forum!
A thick white discharge can be due to ovulation time or due to pregnancy if there is a past history of unprotected sex. Yeast infection to begin with only causes a white vaginal discharge without causing itching or pain during sex. A PAP smear and vaginal swab test should be done.
Since there are yellowish white chunks, chances of yest infection are high. Yeast infection or thrush is at times very difficult to treat. You may need to take oral antifungal pills twice a week for 3-4 weeks along with local application of antifungal cream. There are many types of antifungals available. Take an OTC antifungal with a combination of two or more anti fungals. Use both oral and local application. At times both partners need to be treated. Provided it is indeed fungus, then only try this. Antifungal tablets are strong medicines and should not be taken otherwise. So start with cream and if it helps, start the tablet. Various reasons for recurrent fungal infection are incomplete treatment, treatment resistance, co-existing dermatitis, diabetes and low immunity.
Since a confirmed diagnosis cannot be given on net please consult your gynecologist regarding this. Hope this helps. Take care!