Late period, negative pregnancy test.

Hello Dr, I'm two weeks late, expecting my period to begin on 23rd June. The last one was on 23rd May, it came a week earlier to the previous period which began on 27th April. I've taken 2 pregnancy tests, it's negative and I have no pregnancy symptoms except for on - off cramps. My periods are usually regular and I only missed it once when I was under a lot of stress preparing for my exams. Just after my period in the month of May I traveled back to Bangalore, India my work location to spend time with my family. I spent an entire evening helping my mum clean the entire backyard, found it very stressful and draining! On the work front Its been very stressful beginning the month of May, I've taken up new responsiblities and find myself anxious most of the times. I usually know when I ovulate cause I experience some pain for a few hours on the very day! My around the month of May, I did not feel a thing which makes me wonder if I did ovulate. Please advice.