Hiya - what are the sedative drops? IT isn't too soon to be worrying, adult cats can take months to settle - I had my scaredy foster for 5ish months, and I couldn't handle him - but 2 months in his new home, he could be handled. Some tips:
- Leave a radio playing either classical music or a talkstation all the time
- Just sit in his room ignoring him, do whatever interests you, i.e read, crossword. Ignoring helps, as they can study you in their own time, and generally get curious. Just spend as much time as you can just being near him without interacting.
- Food can be a big help in gaining trust, I used sliced meat and put it closer to me, until he was taking it from my hand.
- Fishing rod toys can help, as they dont have to have that much interaction with you.
- Rescue Remedy can help.
Time and patience are very big keys in this.
I decided when I had SJ that I was going to give him 6 months, and if there was no improvement, however slight, that we would look for a farm home for him. Not all adult cats can tolerate living in a home environment, and I think it is something you do have to be aware of. You could also do with looking out for things that indicate stress, such as hair pulling, cystitis, in case there are signs that he isn't happy.