@Sally5343
Read this whole thread, all 5 pages, in which there are many solutions discussed.
One of them may well be relevant to your particular problem.
You could, though, start by putting your router as high up as possible in the lounge,
If my posting answered your question, please click ‘Accept Answer’
(As long as you started the thread, and haven’t already accepted an answer)
If you liked my posting, please click ‘Thanks’ (the thumbs-up icon)
If you disagree with my posting, say so below, and I will see if I need to mend my ways 🙂