All mutual fund gains accumulated through S.I.P. in the last 8 months have been washed out in a week. Should I be worried?

Dont be worried if you are a long term investor. Keep SIPs continued if the funds you are investing in are good performers (in relative terms).

If you are not invested into direct plans of the funds, then consider switching over to direct plans which results in upto 40% more corpus over the long term. That is the impact of eliminating compounding commissions.