Nausea and

I was worried about taking antidepressants, and they have had some side effects, but today I feel pretty hopeless, run up to Christmas, haven't a word from family for a month, and lot longer since I had detailed news, job I thought I could definitely do doesn't look like I've been shortlisted. I'm getting very tired, yet don't sleep well at night, I've nausea yet I continue to eat, keeping my strength up, supposedly. I've become more lethargic as well, used to take the dog out every day but the last couple of days I haven't been bothered. What is wrong with me?