What's Going On???

I'm on CD 33 and approximately 14dpo. My cycles are ALWAYS 28-30 days. I've taken pregnancy tests at 9dpo, 12dpo, and 14dpo and all 3 are very clearly negative. The picture is over today's test at 14dpo and there is no 2nd line anywhere. I'm a little nauseous, and I've been cramping for like the past week. My fiance said my cervix was high, firm, and closed. My cm keeps changing between creamy and water throughout the day for the past few days. What's going on??? Should I go and get a blood test done?