That period of time when we are waiting for the results of something we fear can be dreadful, halfbaked75. It can only be worse since you are already suffering from anxiety and depression. Until you know for sure what your son is diagnosed with, I suspect you can expect to be in a bad way, so if sitting on the couch and watching TV for a while is all you can manage, then I believe you need to be doing that. You say you are still taking care of your son, so that is the most important thing done. Once you know the level, if any, of austism he has, I feel sure that you will be able to pick yourself up and work out a plan, considering your training and the fact that you love him very much. Being able to move forward and not just tread water - which is what you are doing at the moment - will relieve some of the stress. It will also mean you can start thinking about what to do with your son's schooling, because I am sure that is the other great worry on your mind. ((((hugs))))...
As for anti-depressant affecting foetuses - I don't know about that. I would like to observe though, that infants in the womb are also affected by the mother's mood. Unless there is a real, high chance of medication hurting your new baby, could you try a low dose? You being more relaxed and calm and coping well must surely be better for baby than being so distressed, even if you need a little help to be that way? By being calmer you will be more able to focus on eating well, getting some exercise and good sleep, and just generally being more confident you can handle whatever life brings?
PS I had/have two children with mental issues, so I am not speaking from ignorance. Each family situation is different but as with any child, there are often enough good times to make the struggling times worth it. You ARE a good mum... noone who cares as much as you do could be a bad one.
PPS Stop googling
you know enough already, and there is no end of bad-news stories on there! May I suggest you go to the library with your son and bring home a couple of bags of storybooks and spend a day or two just cuddling and reading, laughing and crying with him?