Wealth, yes, but my heart's a bit lonely (5)
I believe the answer is:
money
'wealth' is the definition.
(I know that wealth can be written as money)
'heart's a bit lonely' is the wordplay.
'heart's' says to take the centre (I've seen 'heart' mean this).
'a' becomes 'amp' (A is the symbol for the amp or ampere).
'bit' becomes 'o' (resembles 0, a binary digit or bit).
'lonely' becomes 'ney' (I can't justify this - if you can you should believe this answer much more).
The middle of 'amp' is 'm'.
'm'+'o'+'ney'='MONEY'
'yes but my' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for money that I've seen before include "Mazuma, ackers or dosh" , "'A fool and his.....are soon parted'" , "Bread" , "Legal tender" , "Medium of exchange" .)