Don't worry! Everyone feels that way, and anyone who says they don't is either lying or is too stupid to recognize their own level of incompetence, lol!
I think a lot will depend on where you end up for your first multicrew job. Mine was a big jump from a 172 to the Q400 with a well-respected regional operator, so a cut or two above a place like Georgian on a B1900, Bearskin etc. (Please, no holy wars... I'm not bashing those companies; I'm just saying they don't put in as much time to train you; that I know for a fact since I have lots of friends in those companies, and can objectively compare things like number of initial sim sessions, number of line indoc sectors, length of ground school etc.) On the one hand, it was a big transition, compared to the guys who had at least a few hunderd hours in a Metro or a King Air or even a Navajo under their belts. On the other hand, some things were made easier because the training program was so rigorous, thorough and structured, and also because the plane is so easy to fly due to automation (when nothing is broken, that is).
Anyway, despite a lot of sim training on both normal and emergency procedures, I was NOWHERE near comfortable on my first line indoc flight. In fact, I told the training captain the truth on that first day - that I'd only flown planes 20-30 times lighter up to that point, and that I had only seen the inside of a cloud a handful of times, and that I felt kind of overwhelmed. He reassured me that I had earned the right to be where I was, since I passed all the required training up to this point, and that it was normal to be nervous. No one expects perfection; they just want to see that you come prepared, so learn those SOPs, approaches, company procedures etc. That made me feel more at ease, but then I still had a moment of hesitation on the runway, since I was PF on that first leg. I put my hand on the power levers and said "I can't believe this is happening... I guess I'm really about to do this". I thought about all the passengers at the back... they must have assumed they were being flown by a qualified experienced crew, and not by a completely lost dumbass who has no idea what he's doing... LOL! I really was a fine mess on that first day! I got through it all just fine though... you just have to keep studying and reviewing and asking questions and paying attention.
For now you can still work on some stuff that gives you trouble. Nav Canada has a VFR radio phraseology guide, for example. Study it, listen to some ATC Live feeds for busy airports, and then go to busier controlled airports for your time-building... and get flight following on the way too! Go with an instructor first if you are really nervous about talking to ATC, although trust me, you're probably not anywhere the worst ATC has seen. I have controller friends too, and spent quite a few hours hanging out in control towers, and let's just say that if you're a reasonable person and ask for a clarification if you don't understand an instruction, and don't turn left when told to turn right, you should be able to survive just fine.
Anyway, good luck, and don't worry about it too much! Just keep a positive attitude, work hard, and you should be just fine!