Sorry if this reply might be a little late, as it's been a month since you posted.
I hope things are okay for you
There are many reasons why a period might be late, or delayed, none of which are immediate health concerns. The fact that you are stressed out about this might well be a reason why you're not seeing anything.
I don't mean to judge or to criticize. But there is always a chance of becoming pregnant, regardless of preventive measures taken. I'm slightly alarmed by the fact that you were not using protection when exposed to even pre-ejaculatory fluid. Frankly, you never know- after all, you can't see a single cell with the naked eye, can you? I can't guarantee anything, but it seems to me that there is not a great chance that you are pregnant, this time around. Again, I don't mean to be judgemental or sound condescending, but the reality is, is that as long as you continue to engage in sexual activity, you will always have to consider the risk of pregnancy. The only way to live without this worry is to abstain from sexual activity.
Best of luck; please tell me how things are with you now