If you CAN do it freelance for a while fyi the tax situation is better. Plus as per above, no, you won't get SMP but if you have worked 26 weeks in the 66 weeks before your EDD then you can get maternity allowance of just over £100/wk.
The same happened to me as newmummy said - and it was a massive ego boost frankly, which is always nice!
Plus freelancing gives you control of when you stop, you can do less days etc.