Question abut pregnancy testing?

My periods are irregular. I had my last period april,14th,it ended april 19th. I had with dh from the 20th to the 5th like every other day. On the 14th of this month (i ume period was due then,although periods are somewhat irreg.) i tested and it said negative,however i am having some major pregnancy symptoms. i didnt test again after that. do u think im not pregnant since it said negative? do u think i tested too early? and did any of you test negative and then pos a few days later? btw,period is still NOT here! ughhh!