Last night two things happened that seemed odd to me.
First - during sex I felt a painful pressure
Second - going to the bathroom I noticed I had a bright orange color mixed in with the (for lack of a better phrase) sex juices.

I am a bit concerned, I don't believe it could be an STD, we are monogomous and both had been checked prior to being with each other. Any advice woould be helpful.

Could be a few things... pressure might have been due to the positioning perhaps or irritation. Are you due soon for your period or has it finished recently?
Orange color may be from some spotting of blood mixed in.
Could be both are from the start of a bladder infection.

Dito to all doulalc said :)

The pressure, I had this issue when I was younger, and I found that going to the bathroom before even starting the foreplay to sex can help. (but before, it kind of ruins the mood in the middle of oral sex to say 'hold on hon I need to go to the bathroom!" hehe )

Hopefully I will start sometime this week, if not I have some major thinking (& testing) to do. It was a well used position, although more rougher than usual.

Thank you for all your time in helping me understand better the issues at hand. :)