Hi Fefe,
i completely understand your fears and concern, I was exactly the same for my whole first trimester. I have had many m/c and had bleeding and cramping from 6-8 weeks this pregnancy. I was in a constant state of anxiety like you and even though I had a few scans that were great, the fear remained with me.
All I can say is that it gets better with time, I am ( almost) completely relaxed about my pregnancy now and enjoying it immensely.
All of your 'symptoms' sound normal and a bit of brown bleeding is very common. I didn't get MS until 7ish weeks and then it was only nausea every second day or so, some people don't get it at all.
Theres nothing much I can say to make you worry less except that it is normal especially in people who have taken a long time to conceive. The best thing I tried to do was take it one day at a time and just try to get through each day without falling in a heap- DH and I look back now and wonder how we got through it.
Just focus on your scan next week and seeing that heartbeat, think positive and try relaxation techniques- when i was feeling bad I would just lie in bed and listen to my fav music on my ipod to get me through. Its a shame your DH is going away, have you got any family members that can come round and visit and be with you?
All the best hun, you are not alone in feeling this way there are a lot of us who have been there xx