Hello A.,
I am also a single mom and when I had my son I was in college full time. My son as also in daycare. My son is famous for his smothering tendancies as he always had to be in my lap. I also felt very frustrated at times after having a hard day at class and coming home to a demanding toddler. There were days when I just wished he would go play by himself. I love my son more than anything you could pass my way, don't get me wrong. However, in general I loved that cuddly side of him. It made me feel like the difficulties of being a single mom were worth it.
I suffered from major post partum depression (thanks for the most part by his father). The thing with my son was that after a day of being with other people, he just wanted to be with mommy. I am all he has. After a while I realized that if I just spent a few minutes playing with him every day after we got home he would be content for awhile and let me do my own thing. If he insists on sitting in your lap then take the opportunity to read a few books with him or count his fingers.
Another thing I did, and still do, is let him help me cook dinner. Obviously he isn't allowed near the stove but I'd take the pan to the counter and let him dump the ingredients in from there. Its a great way to spend time with him without him smothering you in your lap. After all, who has a lap when they stand?
Something else that has also worked like a charm is that we established a ritual every night where we would sit down together and watch a 30 minute video before bed. That was strictly time for the two of us. Knowing that he would get this 30 minutes of "mommy-only" time not only made it easier for me when I was too busy earlier with dinner or dishes to play, but it also helped him to go to bed knowing that his mommy loved him and would take the time out for him. Chances are he may want to sit in your lap. Try seeing if he will sit next to you and snuggle into your side, you may have to try that a few times. Another thing to try is to lay down with him on the couch during the video. With him laying in front of you he can't really attach himself in a way that may upset you.
Try to enjoy this cuddliness while you can though, if you need to talk to your doctor about how you are feeling, it is never a bad thing to do this nor does it make you a bad mom. It makes you a good mom because you are trying to do what is best for you and your baby. Believe me, the cuddles will become few and far between before long. My son will be 4 next month and rarely sits in my lap. A year ago you would have seen an entirely different picture.