Ahhh Brooke my lovely, you sound like you're having such a hard time of it. In my first pregnancy I cramped for weeks and weeks. Was sure I was going to get AF but it never came. I was told at my booking appt that it is just everything inside started to stretch and change for your little one growing.
You're not a horrible person hun but I'm not sure if keeping it from your dh is a good idea, we all need support no matter what the outcome. I understand what you're saying and you trying to protect him but I'm sure he would rather know and be able to support you? Even if it is just be bringing you a hot water bottle and a cup of tea (decaf) every now and then.
With regards to scans, I think it is 6 or 7 weeks for them to be able to see and hear the babies heart beat but I know some EPUs won't scan you until 8 weeks so you may need to pay for a private one if you want one before 8 weeks. I would speak to your GP again tonight and see what they say. FX the pain is from the UTI and unrelated to your little bean. Let us know how you get on. X