You still could be. Some women do have bleeding around the time of their period being expected. It's usually lighter than normal though. Take another test now as it has definitely been long enough. If it is negative, then you are probably not pregnant and can try again next cycle. Best way to conceive is to track your cycle. Day one of your period is cycle day one. On day 10 of your cycle, begin to have unprotected sex EVERY OTHER day for the next 10 days. That usually catches the egg. good luck
If you just had your period, it's not likely that you are pregnant. If you conceived on July 11th- your test should come up positive now, if you are expecting, but it also sound like you think you conceived more around July 4th? Either way, the test should show you if you are pregnant or not by now. The symptoms you are experiencing could be from many things- even just hormones from your cycle.
You can wait another week and test again, but if I'm understanding your time line correctly, it doesn't sound like it's likely you are pregnant.
Best of luck and let us know how you are doing!