MsAshamed, how I feel for you. It sounds like your ds is a demanding child. That is not to say he will not blossom or get better, much much better, at a later stage. In fact, for my 'spirited' dd, 3 was the turning point, but really only just the beginning cusp of it. Your ds will probably still be more demanding than other children, but believe me, when I would be writing the same as you at 3, I actually look forward to spending a day with dd now at 4.8.
My dd needed constant attention 24/7 since she was born and was difficult in almost all aspects - sleep, eating, playing independently. But if I had to decide what was the Hardest Bit about her early days, I would say the inability to play independently and constant demands and tantrums. Because then, there is very little time for you to be in your own skin. Which can be very very difficult if you are used to having a reasonably successful and directed career.
The only way I coped was to build in lots of breaks from my dd - 30 mins a day is hardly enough. I mean hours.
I assume your ds has had childcare experience since you work. Dd was like a different person in nursery (I cannot figure out why) - but she does not whine as much, eats very well, sleeps on her own (sob) and enjoys the hustle and bustle. The nursery workers think I am must be talking about a different child if I asked whether she tantrummed that day. Hopefully, your ds has a positive experience as well.
In terms of options, you could consider:
(1) using more childcare than you need. I work pt but use ft childcare, with the difference used to catch up on chores so that I clear the decks for dcs when they get home. Less knee-hugging, whinging and tantrums all round.
(2) Or if not affordable, go ft (as another poster suggested). I assume you know about the surestart grant that kicks in on the term after your ds' 3rd birthday which will subsidise your childcare costs by £100+ a month.
(3) Go out as much as you can when you are with ds.
(4) Make sure your dh does his fair share. My dh takes the dcs out on weekends to give me sheltered time, so much that the staff at a particular cafe can't believe my dcs have a mother.
(5) I co-sleep - it works for me, but I appreciate not for everybody. My dcs are so easy to love when they are asleep. I give them kisses in the dark of night and they cuddle up in the warmth. It helps me to reconnect.
(6) You don't have to believe this, but ... it will get better, possibly very soon. Once your dc is in school, there will be no looking back. Lots of experienced mothers on mn do say that 5 is the turning point.
(7) The last you want to hear, but ... have another dc. It is incredible how quickly my dd started having a lovely playmate in my ds (3 year age gap). Now they are best mates and sworn enemies in turns but the best thing is they leave me alone some of the time. All I need to do is mediate squabbles, which is a darn sight easier than what you are going through now!