Welcome to the site !!
Yea it sounds like the clutch .... you need to take it apart and check the plates and springs , and see if they are within spec (most likely not if its slipping that bad) (do you have a Owners or Service Manual to check the specs , and a caliper to measure the plates and disks and springs ???) , not sure of your mechanical ability , but its a fairly straight forward job and if you can do basic maintenance on the bike , you should be able to service the clutch with minimal difficulty , providing you have the proper tools and manual for torque specs , etc. , also check the fluid , if it stinks , and is brown/silver looking then it is most likely toast and needs a good flushing of the case with oil till its clean , also after removing the plates and disks , you need to look at the clutch basket itself , if it has grooves like shown below , then it will need replaced as well
This is what a worn/junk clutch basket looks like (the notches make the clutch grab/jerky , it needs to be smooth)
