I think I might be pregnant, but doctor's test result says negative?

my bf came on my virgina first week of june nd I saw my period 16th of june, and from 26th of june I started feeling strange sensation in my belly especially after eating, I tried using home pregnancy test strip and its negative, went to the doctors same negative, but I kind of feel bloated and tired, and I don't know if its too early for the pregnancy to be detected and if my period was to decieve me, please can I be pregnant and when does fertilization take place, am scared and confused, please don't be harsh when replying I've done enough crying I wish I had a mum to talk to but she is late, this was my first time and its not like we had