You do need to attend your follow up, regardless of gestation and it's important to seek medical advice if you are at all concerned.
As has already been said, there is no "normal" for spotting following a termination - for some women it lasts days, others a few months. The only time to be concerned about the bleeding is if it's excessively heavy (soaking a pad within an hour is what I was told afterwards) or when it lasts for an excessive amount of time (again, I was told after 10weeks it should have stopped).
As for the sex. You are advised to abstain completely in the two weeks following. If you do have an infection then it would depend entirely what it was on the question of whether you could have passed it too your husband. Certain things which are common after an abortion (such as bacterial vaginosis) are not sexually transmitted (although need to be treated as they can cause pid if left untreated) but the chances are that you would be very aware of having something like this (i had it after my mirena insertion and there is a very noticable pain amongst other things).
Try to relax, post abortion complications are rare (whichever procedure is used) but you do need to see a doctor to rule out the possibilities of infections. Call the clinic or your local doctor and make an appointment, it may be scary at the time but you will feel better in the long run