should I be worried

I believe I was roofied the night of August 27th/early the 28th. While I don't have any proof of anything I woke up at my friends home with no pants or underwear on. There were men there that night. I am worried someone sexually assaulted me and I do not remember. I can not remember a single thing after leaving the bar.
I had what I believe to be a normal period which started on September 22nd and lasted 10 days. My husband and I made love on the 3rd of October and on 21st I tested positive for a pregnancy test. Giving me a estimated due date of June 28th.
I have read so many things about bleeding before a pregnancy and that it is not always a true period. I am terrified that I was assaulted and I'm pregnant with their child.  Could this be theirs or am I freaking out for no reason? The math tells me it can't, but am so very afraid.
My husband will most definitely leave me. Any advice? I do see the doc next week for an ultrasound - went to a clinic to have one a week ago and they said I was just barely 6 weeks, but I don't know how talented they are at ultrasounds and if she was just basing that on the first day of my last period.
Help.........

[AnnieBrooke]

If you were roofied and if it caused a pregnancy, the pregnancy at this point would be twelve weeks along.  In other words, you'd be six weeks further along than a pregnancy that was conceived October 3rd.  An ultrasonographer will not confuse a 12-week pregnancy with a 6-week pregnancy.  Given that he or she was even looking at the screen at all, if he told you that you were barely 6 weeks along, you did not get pregnant in late August.  

Are you intending to do anything further to investigate or report the possibility of physical assault?  At the very least, if you are too afraid of your husband's reaction to go to the police, you should get tested for sexually transmitted disease.

I am sorry this happened to you.  

[utmom7876]

Thank you AnnieBrooke. I have thought about the police report, but have no absolute proof it happened or let alone who did it. Does that matter?

[Clysta]

Did you ever leave your glass unattended or let someone else get you a drink?

It can be hard to prove if you were or not, especially if you're not even sure of the details. In my experience, you know if you've been sexually assaulted or not. It's extremely painful later on, and at times can also cause bleeding.

[AnnieBrooke]

If you wound up at a 'friend's' house without underclothes on, did you ask the friend about the incident?  Someone must have seen *something* that night.   I am under the impression that the whole point of rohypnol is that it removes resistance and to some extent consciousness, so possibly someone who was not resisting might not be in extreme pain afterward.  If you think your friend can shed some light on the situation, give some names, or give you other details of the evening, I would consider talking to the police with what you learn.  Someone could be out there doing this to other women.